Speaker 1: Welcome to another episode of the Crime Pace of BONDI doesn't.
Today I'm here with doctor Andrew Hip, director of the Herbarium,
and senior scientists and researcher in plant systematics at Morton
Arboretum just outside Chicago, and we're going to talk about oaks.
Andrew you there, I'm here. Okay, great, So let's just
get right into it, man. I mean, this is a
huge subject. This is one of the most ecologically successful
plant plant genera in I mean, it's huge all over
the world, especially in Mexico, temporate latitudes in North America.
Europe's got quite a few. How many does Europe have
compared to North America? Are there more in Europe than
North America? Sam amount or what? No?
Speaker 2: In North America? North America in the US is like
ninety species, Mexico Central America like maybe one sixty, and
Europe has got what's the number, Europe may be on
the order of twenty five for thirty or so.
Speaker 1: Oh wow, yeah, so not as much, yeah, not as
much of us?
Speaker 3: Yeah yeah.
Speaker 2: And then East Asia's East Asia's up near maybe one ten,
one twenty. I actually haven't I've counted up by lineage,
but I don't think I've counted up by region in Asia.
Maybe so because I think that Cyclobalinopsis, the ring cupped oaks,
which are endemic to East Asia. I think those number
ninety species.
Speaker 1: Is that a genus Cyclobalinopsis, No section, it's one of
the lineages, Yeah, that arose from the oaks.
Speaker 2: Yeah, so it's part of the oaks.
Speaker 1: So we're still just talking the genus quirkers, because I
know there's some other weird genera in Asia too, just
like there's not the Letocarpus in California, the tan bark oaks.
Speaker 2: You get, well, what exactly so you got you have them.
So if you go back, like the oaks originate like
fifty six million years ago, and here I'm talking about
the oak genus up in the northern temperate zone like
a you know, maybe straddling North America what is now Greenland, Europe,
somewhere up in that area. The oaks probably arose around
fifty six million years.
Speaker 1: This is really warm back then. I mean, this is
we're talking Eocene, Paleocene, Eocene. This is like.
Speaker 2: Totally this is right before the hottest time that we've
seen in sixty million years, you know, So it was
like ten degrees centigrade warmer than it is now worldwide.
Speaker 1: Okay, so yeah, so this is a this is so
that you could see how this would be a ripe
environment and climate for for plants. So it's if people
hear that and think, oh, Greenland, they're not thinking about
it wasn't covered in fucking ice and et cetera yet.
Speaker 2: So no, at that point, it was like this is
the like where we're standing right now, where where you
are in Texas, where I am, and well for sure
where I am in Chicago. This was broad leaved evergreen
forest down here at this point, and the only temperate
forests were little outposts up in the Arctic.
Speaker 1: Yeah, so Chicago back then was like the climate of
southern Louisiana probably probably, so yeah, okay, okay, cool, all right,
So moving to move around. So they they originate there,
and they're they're in uh the family PAGECI in the
order of for gaillies. They're not. There's no oaks. There's
no native oaks in the southern hemisphere.
Speaker 2: Right, boy, there's a couple squeak just gets out of
the equator and you know in Southeast Asia.
Speaker 1: Yeah, I mean just barely just like pines. Like there's
no there's only like one Pinus species in the Southern hemisphere.
I think it's in like highland Indonesia. But generally it's
like a this is a Northern Hemisphere genius. The Southern
hemisphere has the n though vegas and the quote she oaks,
the castine a c which looked like pine trees. But
we're just talking qurcas. There's there's no carcas really in
the Southern hemisphere.
Speaker 2: That's right. So when you're looking at the when you
look at the oak family, the oak family dates back
probably closer to eighty five million years ago, maybe it's
that probably a little bit younger than that still, maybe
maybe more like sixty five million years anyway, I have
to look up the dates on that. But those genera
have spread more widely. So you have Lithocarpus, which is
an East Asian endemic genus. Now you've got right, So
you've got motho h You've got oho vegas in the
Southern hemisphere. Yeah, but these these things all are related
to oaks, but none of them are are the true oaks.
Speaker 1: Okay, really quick, what I'm getting too distracted, which I'm
well known for is the lithocarpus. Are those insect pollinated?
Are they win pollinated? Like like the true oaks?
Speaker 2: They are insect pollinated?
Speaker 1: Wow, just like the tan bark oak. Just like not
the litho Calcornia.
Speaker 2: Yep, yep, wow.
Speaker 1: That's cool. Okay anyway, sorry.
Speaker 2: Okay, as you were saying that that, well we can
get Yeah, that one is sister to all the rest
of the oak which is kind of cool. You've got
this one insect pollinated species in California, right, that is
sister to like the four hundred and twenty five true oaks.
Speaker 1: Yeah. It's such a great species, man, there's so and
they grow so fast and they're just fucking beautiful trees.
I miss them. They're anyway. Yeah, we're gonna be all
over the place in this podcast. That's fine, but uh so, okay, well,
going back to going back to the uh the genus
corcuso it originates probably in where like like Western Hemisphere,
Eastern hemisphere, northern latitudes where where.
Speaker 2: It's northern latitudes, and it's really unclear. We don't have
a clear I mean, the many of the many of
the relatives of the oaks are East Asian Butthocarpus is
limited to us in North America. There's a chance that
knows Althocarpus, that one species may have been you know,
in East Asia as well, because there were good connections
between western North America and East Asia at that time.
But it's unclear. So we suspect that the that the
ancestor of the entire oak genus was widespread. And to me,
what makes most sense is that this is a widespread
population that was kind of straddling the continents. Europe, Greenland,
North America are all squeezed pretty close together at fifty
six million years ago, and they're spreading apart. So you
can imagine a situation where you've got this widespread population
moving between the continents. Maybe it's even a few species
that are interbreeding, right, so, but it's a it's an
interbreeding population and as the continent spread, the first speciation
ancient deep split that we see in the oaks is
between Eurasia and North America. That is the first deepest
split in it. So that's where you when you look
at the genomes, you can see this deep, deep division
between those two that dates back to somewhere between fifty
and fifty five many years ago or.
Speaker 1: So in what are those clams, I mean we talk
a subgenera or sections or.
Speaker 2: What what we call them now yet so then as
of twenty seven, so the classification that I'll talk about
all goes back to twenty seventeen. It was written by
Thomas Dank who's a really great palaeobotanist and taxonomist, and
he got a group of people together to write a
book chapter sort of translating what we know about evolutionary
history into a taxonomy. So as of that publication, those
are two different subgenera. So the Eurasian subgenus is subgenus Sarus,
so we're talking about Quercus is the genus. Subgenus Sarus
is today limited to Eurasia. And then the North American subgene,
the American subgenus is subgenus Quercus. Look, it's a little confusing.
You've got Quercus is the genus, the subgenus is Quercus,
and that is limited mostly in North America, but there
have been a couple of migrations back to the Old World.
Speaker 1: So subgenus is it series and then subgenus Quircus.
Speaker 2: Or what yep, Cerrus is ce r R S Eurasian.
Speaker 1: Okay, okay, cool, But that's that's the evolutionary fork in
the road. And bio geographically speaking, that makes sense too,
because you know, the way I I guess the way
I look at it too, is you know, the circumference
of the Earth obviously is a lot smaller at higher latitude,
so it's not such a big deal for things to
go back and forth between continents, especially if they're not
that far apart tectonically. Back then fifty fifty six million
years ago, and and.
Speaker 2: Then is it right?
Speaker 1: Yeah, and then as the climate starts to cool and
things change and they can move down and lower latitudes
because they're adapted to cooler temperatures. Generally speaking, they kind
that's like the fork in the road. I mean they basically, yeah,
one goes towards North America and one goes towards Eurasia.
So that's right. Sense.
Speaker 2: It's worth remembering that even at forty until mammals are
even moving between the continents a far north until about
forty nine million years ago. Now, plants are still able
to move between them, but as the temperature is cool,
they get shoved southward right right, and so you've got
the continent spreading and those plants all moving away from
each other where the temperate you know, these little outposts
of temperate forest that we got in the far North
when the globe is largely tropical. And here we're talking
again still between fifty five, fifty six and fifty million
years ago, but you've got these areas in the far
North where it's dark for a lot of the year, right,
and it's light for the rest of the year. That
favors the evolution of deciduous plants. Ah, very good chance
that decidiony originates in parts due to that seasonality. Seasonality
will generally tend to favor deciduous species. It's one way
of avoiding difficult times.
Speaker 1: Yeah, you can avoid just going just getting ready late, right,
exactly right, right. Dormancy evolves, you know, seasonal dormancy evolves
in trees in the tropics where they have a pronounced
dry season. And also most people think that it just
evolves in response to cold temperatures the winter, but not so.
It can evolve in response to not having light for
half the year either. Because you're so high, high up,
so high latitude. So this is okay, So this is
fascinating stuff. So, but there are oaks have always been
wind pollinated? Are there's no insect pollinated members of the
genus Quircus, correct.
Speaker 2: No, and it's one. So when you define oaks, like
what makes an oak and oak? Because you got this
this whole family. You have a cluster of species, a
cluster of or together that some of several of which
produce acorn like fruits. You talked about, Note the Lithocarpus
endemic to California, it's got an acorn litho Carpus, which
is again this other genus that's widespread in East Asia.
Some of its species produce fruits that look like acorns.
Cast Anopsis, which is another East Asian oak family for
Gaycee genus, produces some acorn species that have acorn like fruits.
So when you get into oaks, though, what shifts between
all these The shift to wind pollination is a big
deal in the genus Quercus. If you look out in spring,
you go walking around in the spring and you look
at the look at the trees. You see in the oaks,
these dangling you know, strings of male inflorescences. These are
called the catkins. They almost look like tinsel hanging off
the tips of the branches. Those are the inflorescences, the
male inflorescences. Each one of those catkins has clusters of
little male flowers on them, and all they are is,
if you've looked closely, you'll see the petals are gone,
the sequels are gone. All you see is basically there
are petals.
Speaker 3: You know, there are floral parts there.
Speaker 2: But basically what you see is the dangling stamens. All
those things are there for is to get that pollen
right out on the wind.
Speaker 1: Yeah. You can look at a wind pollinated flower. Yeah,
you can look at a wind pollinated flower on any
wind pollinated plant, and if you know what to look for,
you can tell this is probably wind pollinated. I mean,
the floral parts are reduced, they don't need to attract pollinators.
The petals and sepals are reduced, right, The anthers are
just out there. You look like ambrosia. You look like
ambrosia flower heads up close, the same thing. Yeah, they're
just getting it out there. And then of course when
you tap it, when it's actually you know, producing pollen,
it you get huge clouds of yell polant coming off.
So but this is so let's talk about floral biology.
The oaks too, because they're they're unisexual flowers. They produce
unisexual flowers. But a plant, an oak tree, will have
both sexes on the same plant. That's known as being
monecious as opposed to dioecious, which not many plants are,
you know, like silk tassels, cannabis, et cetera. They've only
got unisexual flowers, but one plant only has one sex
of flower on it, So the plant is functionally functionally unisexual,
you know, male or female. But oaks are oaks are monycius.
They've got both sexes, but they they're unisexual flowers. So
this this evolved. And then that they've got the catkins
like we talked about, but then they've got these the
female flowers. The piste late flowers are tiny. They're really
hard to find in some cases unless you know what
to look for.
Speaker 2: Right, that's right if you look along the branch, so
about the time that the catkins are coming out, so
in our area, look around in like afl or even
late March, depend on the year. Look on the branch
and you'll see what looks like little buds, and some
of them will start to put out the stigmas, and
it's going to look like three little curved lobes that
come out of the tip of each pistol of flower.
This is the female flower. Those are there. They're going
to be reddish yellowish oranges. They're going to be look
bright and healthy and ready to grab pollen. And about
the time that pollen is flying, the pollen will the
anthers from the stamens will crack open and each one
will release a thousand or more pollen grains, so billions
of pollen grain, tens of billions of pollen grains off
of every tree. And they fly in these clouds and
they may go one hundred meters, they may go five
hundred meters in some cases that we know of pollen
effectively pollinating oak trees thirty kilometers away, so they can
fly quite a little distance. Yeah, and then they and
then these pollen grains hit. Most of them are going
to fly them against the side of a car. They're
going to hit a leaf and just do nothing. They're
going to land on a big blue stem and do
have you know? All that work for nothing? But a small, small, small, small,
small percentage of them will land on a stigma of
the same species or a close relative, and you may
get ten, fifteen, twenty pollen grains all landing on this stigma.
And what the stigma does is it stimulates them to grow.
So each pollen grain man grows a little pollen tube.
That pollen tube pierces the surface of the stigma and
it starts to grow down the style, which is the
neck that connects those stigmas down to the ovaries, right,
and it grows down and down, And these pollen grains
are racing, right, and so if the if one is faster,
is more fit, it's going to reach earlier. If one
is from the wrong species, there's a very good chance,
not always, but there's a very good chance that that
the that the female flower, that is the flower is
gonna block it, is gonna stop it. If one is
from the same tree, the female flower will often block it.
I was just about right, And they're trying to get
down there, and then they all get down to the
point where then like the bass of the style, and
then they stop and they and they may stop for
weeks or months like in the white oaks, or they
may stop for a year like in many of the
red oaks. Not all of them, but many of the
red oaks. And then after that they start up again
and they try and get down to an ovule, and
these pollen tubes are raising each other. They try and
get down to the ovule, and some of them never
wake up after that delay. This is called delayed fertilization.
So some of them never wake up. But it's usual.
Speaker 1: The way hold on is this delayed fertilization is this?
This is a thing that doesn't happen in a lot
of angiosperms, right.
Speaker 2: This happens in I have to look up the number
of families. There might be like twenty five plant families
or so.
Speaker 1: There's been some, but it's not common.
Speaker 2: No, it's a special thing, and it's it's throughout. You
mentioned the group of the gailies, this cluster of families
that includes the Birch family. It includes then then Jugli
and Daisy, the Walnut family, includes the Oak family, Beach family.
These all have delayed fertilization. So it's a cluster of
closely related families that all do this.
Speaker 1: And what what does go? Why? Why why do they
stop and take a break. They're just they're just pooped,
they're just wiped out. Or what I mean, what a
great question.
Speaker 2: No, no, no, no, no, it's like it's costly, right, it's
risky in a way for the tree to do this.
So that suggests that there's some advantage. So I've seen
there's a there's a couple of interesting theories. One has
been that if you delay fertilization, it gives the pistol
at flower more time to select among pollen grains. Okay,
so that's one possibility. Is that it that So that
means that and that makes sense right, so the female
flower does not want to waste her energy on suboptimal pollen,
gets the female opportunity to just select them.
Speaker 1: Yeah, this is this is fucking blowing my mind. I'm
so glad. I asked, you know, I wasn't expecting this
in depth, but this is like, this is three hundred
percent better than what I was expecting. This is Oh,
I'm so glad.
Speaker 3: I'm glad.
Speaker 2: I said, you're the had Wilson principle, like the breath.
Speaker 1: No, this is odd. This is like in depth because
I wonder about this ship. I'm like, you know, there's
not just one Poulin grain landing on a stigma. There's
got to be twenty thirty. Sometimes you know, how do
how does what gets selected?
Speaker 2: You know there are and they're duking it out. But
here's another possibility. Also, go Joey is my colleague men,
dang at you non university. She's amazingly does this amazingly
detailed pollen work. She has studied delayed fertilization in I
think it was queer to zacutissima. It's one of these
Asian species. And what she found is, she said, Okay,
we knew already that the pollen tubes get delayed down
at the base of the style. But what she suggested
is that in fact this may play almost like the
opposite role of what I was just saying, is, instead
of like winnowing out things, it actually gives everyone a
chance to start over again French, right. So if you
land on the pollen on the on the on the
on the stigma and your pollen tube grows slowly, this
gives you one more chance because everyone gets stuck at
a second.
Speaker 1: This is Andrew. This is there's a turn into like
a very holistic approach to fertilization and angiosperms. This is
very I feel already you know in this fuck that
day and age we live in. Everyone's fighting over stupid bullshit.
Everyone's turned up. The left is constantly attacking itself. That
kind of yeah, this is like, this is good. This,
I feel cleansed. This is like psychologic therapy. Does I
got a question? Does another really cool plant? I don't
want to go too far off here, but another really
cool plant in the order for gaillies is Comptonia peregrina.
Uh I forget this's what do they call it? Sweet fern?
It's a shrub, It's a woody shrub. It is fucking gorgeous.
It's one of the coolest native plants. If you live
in the upper latitudes and you don't have that, you're
not trying to get this in new yard, You're an asshole.
This is I'm just kidding. Of course, to anyone listening,
I said, you just don't know about it, But now
you know about it, you gotta look it up. Does
this do delayed fertilization too or what?
Speaker 2: So far as I know, as far as I know,
everything in the Fagales and I Joey, I can't remember
which genera have and have not been studied, but I
believe near a Casey which is the family that includes Comptonia.
The amazing sweet furniture've gone Like if you've been in
horse pastures of sandy Field in the north Woods. Yeah, man,
and you've smelled this this sharly sweet smell. It's wonderful. Yeah, yeah,
it's great.
Speaker 1: Yes, and it just looks cool. It's just a beautiful plant, man,
And it's and the seeds can live in the seed
bank for like a century or two. I mean it's yeah.
There was a paper that came out where it was
those the seeds were just they were I forget what
the methodology was that they figured out, but but the
seeds had been laying dormant, uh in this forest because
this is not a this is not a shade town
or plant. They've been laying dormant in this forest. The
forest got cleared and they popped up like in numerous
places and there wasn't any nearby and it was anyway, Yeah,
really cool plant. Can you put me in touch after
the podcast with someone who studies castinacy in the Southern Hampshire,
like a southern hemisphere equivalent that you do you know what?
Speaker 2: Yeah, okay, cool, Okay, I'll look I'll look around and see,
I know somebody can put you in touch with who
I don't know, someone immediately she will.
Speaker 1: Okay, cool, right anyway, Okay, so I'm moving along. So
we got delaid fertilization because this with another thing about
oaks is it takes a while for those acorns to mature.
A lot of angiosterms, a lot of flowering plants, they
flower and they're producing fruit within you know, six months tops.
Speaker 2: You know, right, So okay, so you've got this delayed fertilization.
And again, so around here in most of North America,
I think most of your listeners probably are. Is there
that the white oaks are all producing annual acorns. This
means that the delayed fertilization is only a few weeks.
The red oaks are almost all, but not all, almost
all have biennial accorns, so it takes them two years.
So in a red oak in the in the upper
Midwest here you get you get pollination in the spring.
Let's say, let's think about the acorns that are fall off.
Speaker 1: Which actually the red oaks.
Speaker 2: This is sarahs Okay. So now this is subgenus Quercus,
but it's section lobati.
Speaker 1: Okay, Okay, subgenus. So we're we're this is all in
subgenus quirkus already, it's.
Speaker 2: All SubGenius quirkers I'm talking about right now. But we
also get two year acorns and cycle of alnopsis. We
also get to your acorns in some of islects, I think,
which is the these are East Asian anyways, so you
get so you in. But let's imagine the red oaks
that are falling in our area right now. Those were
pollinated in twenty twenty three in the spring. The pollen
raced down to the base of the style and sat
there through the summer of twenty twenty three through the
fall of twenty twenty three, through the winter of twenty
twenty three and twenty twenty four, and in spring of
twenty twenty four, those pollen grains started moving, those pollen
tubes started moving again, and they only successfully fertilized the ovules.
And I say ovules because a couple or two or
three mile agap fertilized initially in spring of twenty twenty four.
Then in an oak typically and I'm gonna say maybe
it's ninety nine times out of one hundred. Typically, once
one ovule is successfully fertilized and begins growing, it will
suppress the others. So here's one more opportunity for competition.
Joey is like, all these all these congrains are racing
to fertilize an ovule. Suppose three ovules get fertilized out
of the six that are in there, the best one,
the one that's doing best at suppressing the others, will win.
So one more chance to compete. Right, So you're trying
to get the fittest, the fittest acorn every time. That's
why when you open up an acorn, you usually find
only one big seed in there.
Speaker 1: Okay, this is okay. So you have six ovules in
a single female oak flour, that's but only one turns
into it and you only get one acorn out of it.
Speaker 2: So usually, but that's not always the case. I was
out in Maple Grove forest preserved this. This was it
this year last year, I can't remember, it was this
year last year, and I looked at a seedling that
was growing in the woods, and I looked at it
and I'll send you a photo of this.
Speaker 1: You'll love this.
Speaker 2: And what you could see is that it was actually
two seedlings that had been smashed together into one acorn
and about one out of a hundred trees. And here
I'm totally making it up because we don't have a
lot of data on this. There was a study in
burrows where they found one population where it was like
one out of fifty we'll produce a two seeded acorn. Now,
when you get a two seeded acorn, these are rare,
and they are rare for a reason. They're selected against
because they grow more slowly, So we have good reasonably
they' selected against because the fighting couldn't stand nutrients.
Speaker 1: Right, they grow more slowly, but there's not really a benefit.
Speaker 2: So there's that's what I think.
Speaker 1: That's what I think.
Speaker 2: They tend to get windowed out.
Speaker 1: This is blowing my mind. So do all oaks? Do
all Corcus female oak flowers that regardless of section or
subgenus have six ovules?
Speaker 3: Yeah?
Speaker 1: Okay, so and to clear out up for anybody. An
ovule is an unfertilized uh seed and then once it
becomes fertilized, then it's the seed what's the what's the
technical name for that, just embryo or what?
Speaker 2: Yeah, it becomes it, it becomes an embryo exactly.
Speaker 1: Yeah, so ovule versus embryo. Okay, So okay, so this
is not so so when all is said and done,
from pollination to actually one the acorns drop is about
eighteen months. It's about a year and a half.
Speaker 2: In the red oak grewp in the red over the
white oak crew. In the white oak group it's closer.
And there's most of the red group because like, if
you get down to Mexico, you've got annual red oaks.
If you get into California, there's some annual red oaks. Yeah,
but then in the in the white oaks, and in
the annual any annual in any of the species that
produced annual acorns. It's like, let me think, maybe like
March to the end of August, or I could do
the math.
Speaker 1: Here, let me let me use this as an opportunity,
let me I'm gonna pause this really quick and save
it one second. Okay, we're back, hopefully, hopefully the auto
ad input puts some of those terrible and obnoxious ads,
which I'm completely against except for the fact that they
pay me in and you were able to fest forward
through it if you're listening. So anyway, Okay, So getting
back to this, Andrew, let's talk about because we have
sub genera which are for the most part restricted to continents,
like like one subgenus to Eurasia, one subgenus to North America.
Is that correct today?
Speaker 2: That is mostly true?
Speaker 1: Okay, okay, Yeah, biogeography in a lot of cases follows taxonomy,
not always, but with most plants. That's why a lot
of plants that were formerly in the same genus that
occurred in both you know, say, I don't know Europe
and North America. Not all of them, but a lot
of them have been you know, actually put in a
two separate generic because they turns out they were they
diverged quite long ago because of that Atlantic Ocean thing
or Pacific Ocean whatever. But but then we've got sections
in North America too, correct, What is it the white
and the red oaks? Now, what what are the sections
and what are the differences case?
Speaker 2: Yeah, so well let's stick with Let's start with the
Americas where there's five sections embedded in the subgenus square Kiss,
and here's what they are, and they sort of split
off in this order. So the one that is isolated
from all the others that we say as sister to
all the others is the red oak section, that section
low body, and that includes I'm not going to run
the number of species, maybe t one hundred and twenty.
Don't quote me on that. Well, I guess it's okay.
Speaker 1: You've done so spectacular on this podcast already. It's okay
if you don't remember the exact number of species.
Speaker 2: Okay, we've got so we got we got a bunch
of those. And these are mostly by any LaGG corns.
You recognize them in most of the flora by a
few features. One is they they tend they have leaves
with bristle tips. Right, So if you look at the
tips of the lobes on the lobe species, or the
tip of the leaf on the unloabed species, you generally
see what looks like a little bristle. In the white oaks,
you may find a little tooth, but it's not going
to be like a little bristle. So think of like
a if you look at a classic northern red oak,
if you look at a black oak, if you look
at an if you look at a scarlet oak, you
see really distinctive bristles on the tips. So that's the
red oak. Grow. The other things that distinguish that. If
you open up the acorn on a red oak and
look the anything in that in that section, look at
the inside of the of the acorn wall, it's hairy.
That's not true of the white oaks.
Speaker 1: Okay, the way, way, hold on, What are those hairs doing?
What are they are they actually trying?
Speaker 2: I don't know what they're doing there. It's just fuzzy
in there.
Speaker 1: Okay.
Speaker 2: Has it got a feature except to be sweet and
nice and something we can identify? I don't know.
Speaker 3: It's like, yeah, right, it's fuzzy.
Speaker 2: The whole the whole group has that. All the red
oaks do, and they cover all sorts of habitats, So
I doubt that it's this. You know that it's a
special function. It's like unique to some habitat or something
like that.
Speaker 1: Right, And the hair is that they're not exposed to
the atmosphere, so it's not like it's doing any reflecting flats.
Speaker 2: I have no idea. Maybe somebody someone on the podcast
and I said, love, give me a holler. I'd love
to know.
Speaker 1: Okay, anyway, Sorry, I'm sorry to distract you. I digress.
Here we go.
Speaker 2: No, no, no, Then there's four other sections that are
all fall in a separate clade. Here, I'm going to
use the term clade. All clade is is. It's a
name of a group of organisms that are all each
other's closest relatives, that all descend from a single ancestor.
So like when I say primates, primates are a clade.
When I talk about birds, birds are a clade. When
I talk about dinosaurs, dinosaurs are not a clade unless
you include within the dinosaurs the bird birds.
Speaker 1: Right, You needn't to be monophyletic. Now, I've told these
listeners they better know what a clade. If anybody out
there doesn't know what monophyletic means, you're we're gonna we're
gonna talk. Okay, we're gonna sit down the top. Okay,
you don't know what monophyletic is, email me. I'll send
you a little diagram. You need to know this because
it's such a cool way to think about anything humans including.
Speaker 2: And it's the whole the whole world is divided. That
evolutionary history is this history is producing clay anyway, that's
part of.
Speaker 1: Oh god, no, we could go on a tangent about that,
because that's so cool. When I learned that, that changed
the way I thought of everything around me. I mean,
that was a groundbreaking shift in my own perspective on
my own life and how I interpreted the world. It
was like, whoa, everything is related, and it takes the
form of these little triangles that branch off from larger triangles,
and it's I mean, it's so important. I mean learning
that about plants, and that's why I always push systematics
and taxonomy so hard. It's like, you know, because taxonomy
wasn't always about systematics. Now it is for the most part,
but there's still constraints to it because you know, at
the end of the day, we're a bipedal primate trying
to interpret how evolution works.
Speaker 2: So I feel the same way. And it's such a beautiful,
exciting vision and only part of the story, but it's
such an important part of the story understanding the Tree
of life. M anyway, Okay, so you got the Red Oaks.
That section sectional body sister to all the rest of
the American Oaks.
Speaker 1: Which are four other sections.
Speaker 2: Which are four others.
Speaker 1: Oh Christ, this is I thought this this, I thought
this was going to be easier.
Speaker 2: Joey, Joey we're gonna make any peeling off. Next comes
the come the intermediate or golden cup to oaks. This
is section proto Balonis. It's limited to California and some
squeak into Arizona, New Mexico and Mexico. This is things
like the Quirkus chrysolitis Curecus palmer. In fact, the oldest
oak we know of in the world is in this section.
It's quirk As Palmuri. It's in southern California. It's a
thirteen thousand year old estimated to be thirteen thousand year
old clone in the hills around Yeah.
Speaker 1: Okay, wait, hold on, because someone's going to ask how
do they know that? How do we know that? I
mean radiocarbon dating on some sort of root tissue or something.
Speaker 2: No, no, no, no, this is a this is a bit
of a digression. But the Quirkus Palmuri story is in
a two thousand and nine article published at plus one,
so you can so it's open access publication. Anyone who
googles like thirteen thousand year old Quercus palmer i plus one,
you'll find this article. And as I recall, it's been
a while since there The article as I recalled. They
did it by actually estimating the growth rate and the.
Speaker 3: Size of the clone.
Speaker 2: So I don't know if there was radio dating in
this article or not.
Speaker 1: But this thing's fucking old, though, I mean, it's really old.
Speaker 2: It's it's old, and it's out of place. That's the
thing that's crazy about it. It's been orphaned as been
as the glaciers receded northward, right, it got sort of
orphaned down here where it's it's down at lower elevations
than the rest of its colleagues, who's sort of you know,
trammeled the hills and gone up up slope following the
following climate change.
Speaker 1: Right, So this is a this is a shrub oak
that produces multiple stems, and the stems, none of the
stems are thirteen thousand years old. But the rude itself,
the individual, that individual specific genome, is thirteen thousand years ago.
Speaker 2: That's right. The claim we're making, the claim the authors
are making, is that an acorn germinated somewhere around thirteen
thousand years ago, give or take a few thousand years,
and it grew to produce this twenty five meter wide
clone that we observe today.
Speaker 1: Jesus Christ. Where exactly in California is it?
Speaker 2: You know, I'll have to look it up and send
you I can send you a bunch of links after
we're done.
Speaker 1: Yeah. I've been hearing about this thing for years, but
I've never actually gone and seen it. But I mean,
California is full of instances like that where you know,
they'll find pack rat midtens with you know, tree species
in it encrusted in piss like pack rats do. Thank god,
you know, kudos to them. You know where the tree
now grows like two thousand feet higher in elevation that
species does. That's been a big clue to you know,
climatic change from the Pleistocene. So it's yeah, that's a
really cool.
Speaker 2: Uh.
Speaker 1: You know, that's a really cool thing to think about.
Is that I wonder if it's producing seedlings. Still, probably not,
because it's like in the I don't.
Speaker 2: Know, I don't I don't know. Yeah, No, I do
know that that particular individual is at risk from developments
would not a sperm maybe not such a surprise, but
but upsetting.
Speaker 1: A bunch of apes who lost their way. That's that's
that's what what we tend to be sometimes, Okay, anyway,
keep going.
Speaker 2: Sorry, Okay, so that's the intermedia. Then the next clade
that peels off that sister to all the rest of
the white oaks. The next one to peel off is
goofy clade of two species only the pontas. Okay, one
of them quickest, sad Lariyena is endemic to northern Cola.
Speaker 1: Is such a cool one.
Speaker 2: Yeah, yeah, and southern organ and the Siski Mountains. And
this thing is sister to a species quirk As pontica
that is limited to the Caucuses.
Speaker 1: It right, So this is old. This is an old clade.
I mean, if that's this whole thing, I mean, that's wild.
There's so many that's another thing. There's so many plants
in northern California, and the Siski use like brewer spruce
Picea Breweriana, Like what's the closest relative is in like
Russia or something. Such an incredible species, by the way,
just fucking weird. You can tell this thing is old.
It just got landlocked here. It's just the time capsule,
you know, that's it's Yeah. Anyway, so keep going. So quirkusidariana,
that's like another small shrub maybe three feet four feet high.
Speaker 2: Yeah, and it will it will hybridize with with a
wide oak with I think it hybridizes with with our
quirkus Garyana. But it's but yeah, it's it's like it's
sort of a phile. It genetically evolutionary isolated species because
it's sister's way over in the caucases and its sister
species has gone in for a whole nother thing we
could talk about when we get to the Eurasian clay.
So then the next group to peel off is all
the rest of the white oaks, and it's only two
sections left. One is Section Yrnees. Now, this is a
group that includes the fantastic like if you've seen the
angel oak, this magnificent southern live oak. That's the section
that that's included that uh Vranes includes that space.
Speaker 1: Oh, Virginiana, Yeah, there you go.
Speaker 2: Crecus Virginia is one of the one of the live oaks.
These are the southern live oaks. The again only like
six species that range from the southeastern US down to
Central America. There's one species, Quircus olioides, which is one
of the few truly tropical oaks, Greeks olioides goes all
the way down to Central America.
Speaker 1: Yeah, oh god, I want to try to go that
where I live, because it's hot as balls where I
live at all times of the year. And that's that
it grows just south of me in tom Alipis we
get few siformists Quirkus fusiformists up there on the sandsheet
and in the Edwards plateau that's also in Varentees, right. Yeah.
You know what blew up my mind about this section
is that I always assumed that uh Corcus fu siformists
was just like a more drought adapted version of Virginiana.
It was just Virginiana that got an ecotype of Virginiana
that got selected for for you know, as the continent
dries out as you move west. But then I read
that paper about this whole section and that's not what happened.
It's its closest living relative is Quirkus brandigii down in
southern Baja, which really blew my mind. I mean that's correct, right.
Speaker 2: It's absolutely well that you're talking about Chanin's paper, right, yeah, yeah,
this is yeah, for anyone who's interested in this group.
Janine Cavender Barras, formerly of University of Minnesota. Just I'm
moving over to Harvard University. H Now, she's done all
this amazing ecophysiological, evolutionary phylogenetic work on this section, an
amazing body of work at Byrantis.
Speaker 1: That's that's crazy, but so so Yeah, I don't know.
I guess I just didn't expect that because Quirkus fusiformists
looks so much like Virginiana could be so hard to distinguish.
You know, you just kind of go by the the
gist of it, you know, like what what sum it up?
You know, like what it looks like. You just kind
of have that feeling. But there's no like hard characters
as far as I know, between few siformists in Virginiana
are there.
Speaker 2: I don't know, I don't know the byrantzis.
Speaker 1: Okay, Sorry, sorry this strikes, but keep going about okay.
But and also Quirkus Virginiana is not it's in a
different section than Agrifolia, which is the California livok bingo.
Speaker 2: Yeah. So when we use the term live you know,
common names, as your listeners will probably all know, common
names can be super deceptive live oak. That term is
often used generally for just evergreen oaks. But when I'm
talking about the southern live oaks, then I'm talking about
this clade that includes Virginiana pusiformis, brent dgi Olioides, and.
Speaker 1: Am Okay, okay, so okay, so in yeah olioid man,
I gotta see that. That's only in Mexico, right.
Speaker 2: Yeah, that's the only place. Yeah, I've not and I've
not been to Central America. I've seen it in I
think in Tamilpas. Yeah, because I've.
Speaker 1: Seen it, Okay, okay.
Speaker 2: And then then the very last group is the white oaks.
So this is sister two by Ronzies, and it's a
lot of species. This has been the most successful clade
of oaks in a way because so.
Speaker 1: What what section is is what's the name of it?
Speaker 4: Oh okay, sorry, this is Quercus subgenus quercus section quercus.
Oh christ right, So this is a yeah, so this
is the one that like when you say this, this one,
you've got four.
Speaker 2: Lines of quirk because you've got four quackuses lined up,
because you got the the oh maybe three, You've got
the genus, you've got the sub genus, and then you've
got the section. You're right, but you got to do it.
Speaker 1: That's the way we're specific matter, man, It's how this
stuff evolves erectly.
Speaker 2: And so the white oaks are are fantastic. I mean
the white oaks have so when you compare and again,
because in the America's ours, our two biggest sections of
the white oaks white oaks section section quercus and the
red oaks section section lobati, it's worth knowing how to
distinguish these. The white oaks all have annual acorns, whereas
in the north most of the probably throughout its range,
most of the red oaks have biannual acorns, and the
white oaks have I have rounded lobes or just a
little tooth at the tip of the lobe on the
lobes on the leaves on the trees, load leaves on
the trees with out loabed leaves. Again, you can have
a little teeth at the tip, but you're not going
to typically get on bristles, and there are some exceptions.
The other thing that distinguishes these things, if you just
identifying them, pick up an acorn, and the acorns of
the white oaks, their scales tend to sort of be
bumpy on the back you'll we call them to ber
kill it sometimes where's the red oaks tend to have
smoother acorn caps scales not not fully reliable, but you
can learn to identic you can learn to recognize it.
The other thing is the bark. The bark on the
white oaks tends to be flatter plate here, whereas the
red oaks tend to have blockier bark. Again, that that
can be a little bit difficult to see.
Speaker 1: Is corcus and sickness in this section?
Speaker 2: Yeah, Gregson signas? Is it true? White oak? God? That
thing is amazing, you know, magnificent?
Speaker 1: Yeah, Oh my god? Who I think it was?
Speaker 2: Coon?
Speaker 1: SOI Kim who used to work at Morton. Yes, he
gave me years a decade ago. He had some extras
of corcus and signas and he gave me one and
I planted it in Oakland, California. And the thing it
struggled for a while because it's not the temperate or
it's not the rainforests of Vera Cruz, so it wasn't
getting enough moisture. We had those dry summers. But it
finally it got established and did well. But I never
got acorns out of it. But I you know, God,
what an amazing tree. Those giant baseball sized acorns. I mean,
that's the largest acorn of any oak right.
Speaker 2: Well, And I love it, Yes, I believe so. And
I love it because that one grows right with Gecas
skinner eye, which is a red oak up in the
same cloud forests, and also with great, big, honking acorns,
and those are two of the biggest acorns that I've
ever seen in my life.
Speaker 1: Was something selecting for big ic acorns? And that, I mean,
do you think there's like some extinct megafauna or something
that was dispersing those.
Speaker 2: I don't know about that. That's a really good question. Yeah,
I don't know.
Speaker 1: I mean, they're just because they can because it's so
warm and it's so warm and wet.
Speaker 2: I don't so maybe so. I mean, one thing we
do know is that acorns, you know, these these great
big acorns have huge cottle eatens inside. The cottle eathens
is just the name for the seed leaves. Like when
you break open a cut open an acorn, and you're
going to see a massive tissue in there. The lion's
share of the tissue is these acorns. And some of
them they fit together like two halves of a Hamburger
bund and others they're fused, but those are the seedling leaves.
They're holding all the food that the female plant, female
flower has provisioned this seed with, and those that food
plays two rolls, two really important roles. One is to
feed the young plants. So when the plant germinates, the
food from these cottle leads just pour into the roots
and get sequestered in there so that the plant can
get a head start, even in a low light environment
before it can start photosynthesizing. But the food in those
cattle leads has a second, equally important role. It's to
lure in disperses because it's feet and so with a
big plant like intact circus and signus has been studied,
they looked at removing cuda eats. So I suppose a
predator comes along, you know, a squirrel or whatever, and
buries this acorn. Okay, great, Then that acorn is probably
gonna germinate pretty nicely if it doesn't get dug up.
But suppose that squirrel eats like a third of the
cotta eat, which is the really tasty part. It will
tend to eat from the portion it's underneath the cap,
which is less defended, has less tannic acid in it
to defend it against the against the predator. You eat
up like half of that cattle. Eating a third of
that kind of eat the plant is still going to germinate.
Just fine.
Speaker 1: Oh shit, really, so that's so wow, because I was
just gonna say, if it's eating it, it's killing the embryo.
But no, it's not.
Speaker 2: Yeah, the cattle. And so when you look at the like,
pop open an acorn, and this is a great time
to do it if you're not in North America, is
because they're dropping right now. Pop open the cap. Get
yourself a pair of burning shears if you've got some,
or a good butcher knife, just use it, and use
a cutting board because you don't want to cut your
finger off. Cut that thing open and look at the
look at the cattle leens. What you'll see is that
the portion right underneath the cap, thick you know, meaty,
the babe, the young tree. The growing tips then sort
of shoot tip and the root tip are all the
way down at the opposite end of the acorn. And
so when the female plant is producing this acorn, it's
becoming suffused with tannic acids. Tannic acid is the same
stuff that we use to tan leather, the same stuff
that turns like the Black River in central was in black.
Speaker 1: This is uh.
Speaker 2: It binds protein. It makes your mouth pucker up if
you try and eat it. If you feed a squirrel
only acorns, that squirrel is going to lose weight because
that acorn doesn't provide enough nutrients and the tannic acid
is sucking up some of some of the proteins that
it needs to live. Uh. But there's less tannic acid
at the sort of north end of the acorn, right
underneath the cap, which is where the growing tips are. Not.
Speaker 1: Wow. Yeah, that makes sense because you look at when
acorns germinate, the root comes out, that pointed tip at
the radical comes out that point the tip at the
other end. So that is wow. So the tannic acid
is not evenly distributed throughout the whole acorn. It's it's
only where the important stuff is.
Speaker 2: Well, it's throughout the acorn, but there's a gradient the concentration.
Speaker 1: Yeah. So and then the benefit is, of course a
squirrel takes this thing, runs off with it, thinks he
just scored a good meal. And he did, but only
the top and then he just when he's done with it,
throws it throws it the into the duff and that
now that thing germinates. So that's he's disperson.
Speaker 2: A lot of the time. Yes, And you can see,
like last year we had a great mass year for
wherecas for the eastern white oak, and a mass here
is a year when the trees produce fruits in abundance,
and oaks are super famous for massing. In that year,
I walk around the woods and I saw all these
quarter third devoured acorns where the squirrels had just like
and they were just like, oh they were they were desulatory.
They would eat just what they wanted and then just
toss the rest away. They didn't care. It is like
like they were just ravaging a candy store. And those
those many of those acorns will subsequently did subsequently germinate.
Speaker 1: God, that's that's fascinating. You're blowing my mind, man, So okay,
well think yeah, the thing I want to talk about
now too, because you'll there's a lot of shade tolerance
for oaks. I mean, they can they love full sun
when they are large, when they're adults, but they can
also tolerate shade for years, right, because you'll go into
an understory sometimes and you'll see hundreds, if not thousands
of little oak seedlings only six seven inches tall. It's
too shady for them to really do anything. They can
just are they like redwoods, they can just hang out
and lurk for a while until a tree falls down
you get some sunlight in there or what.
Speaker 2: I think it's real context specific because like in our
woods and in sort of in the rich soils around
southern Wisconsin northern Illinois where I've spent most of my
time botanizing, you tend to see if you get a flush,
like we've got a ton of seedlings right now from
last year's mast of Quercus alba, which is the eastern
wide oak is the king of the forest. If you've
read PD's wonderful Natural History of Trees, that's those ceilings
are not going to last forever. They'll stay suppressed for
a little while. But when I get up to northern Wisconsin,
I do see more of this stratification where you get
where you get trees lurking in the understory. Now, I'm
not a community collegist, so I haven't studied this in
any detail. But my sense is that this is very
context specific, and as a consequence, we're not seeing oaks
replacing themselves in most of our woods. Around here. There
is kind of a reproduction crisis really. Yeah. Now, and
I've said about all that I know about that. I mean,
what's influencing it probably fire. I mean around here we're
at the edge of the Prairie province, and around here
the forests are adapted to the savannahs. Forests and prairies
are adapted to fire. But that whole fire regime shifted
in the early nineteen hundreds as we started suppressing fires.
So as a consequence are not seeing kind of ocreute production.
Speaker 1: We used to do. Yeah, fire suppression really spilled. I mean,
it's crazy how many people don't, even in the eastern US,
don't realize how important fire was. I mean, and it's
not just because invasive species, though that the invasive species
problem is made it worse because that really small there's
a lot of the understory. But I mean, even without
invasive species, you've got to burn that stuff off of
for a few years. It's it's healthier for the forest.
I mean, it's healthier, not only for getting rid of
ticks and siggers and insects, et cetera. But also for
you know, just creating an open, healthier forest. So you know,
it's with lower density, right, I mean, because you've got
too much stuff growing in there. Not everything can thrive totally.
And so even in like oaks savannahs in the Chicago area,
fire was still pretty common. I assume like a lot
of those oaks are fire resistant once they get to
a certain size.
Speaker 2: That's right there. Fire some are like it's a really
neat experiment that was done at the UW. Madison Arboretum
in the eighties where they had a savannah that had
gotten clogged with black oak grubs. These little ones, because
they hadn't been burning for a long time, they literally
couldn't get a fire through. So so what they found
is one once they could, they did a really cool
experiment where they like killed off thousands of little baby
black oaks with black oak wilts with a strain that
was already present on the hillside. They trenched around the
whole savannah they were restoring to make sure that the
black oak wilt wouldn't travel through the root grafts, right, yeah,
exact well, it's a It was certainly a strain that
was present on that hillside already. You know what the
genesis of it is, I don't know.
Speaker 1: Yeah.
Speaker 2: And then but then once they could get fired through,
what they found is that many of the younger black
olks would repeatedly get burned down to the ground, burn
down on the ground, so they just keep growing over
and over and over again. You find this with burrokes too,
and so you get the little shoot being burned down
and all that energy that would have gone into that
shot being stored in the roots. So you can get
a root that is, you know, eighty years old, and
a shoot that's just up from that one ear But
give that shoot then six seven, twelve years to get
a foothold, then it can resist the fire.
Speaker 1: But if you've got an eighty year old root, I mean,
that's gonna have a lot of juice stored open it.
I mean that thing is like a battery. That is
good that that's exactly right.
Speaker 2: Yeah, Yeah, And I think I feel like there's a
passage I read and it may have been in John
Muir in sort of My Boyhood and Youth where he
talks about the someone again, if someone remembers that this
was somebody else who said this, but around the Madison Capital.
I think he talks about all these oaks shooting up
in the wake of fire suppression. Yeah, and it was
exactly that, Joey Wray. You had all these root systems
were growing, growing, growing, and they were stepped to jump
once the fires was they released from fire.
Speaker 1: I think that this is a good talking about these
massive root systems, is a good segue into another topic
I want to talk about, which a lot of people,
especially if they're in the Midwest or Northeast, will not
be familiar with. But the habit the phenomenon of scrub oaks,
which are huge colonies of oaks, like you know, Sayqurkus
PALMERI like we just talked about, or Corcus. I've seen
some really cool ones on sand dunes in West Texas,
but you essentially get oaks. Corcus Vexxinifolia is another great one.
I believe that produces actually just straight edible acorns you
can eat. There's another northern California mountain one. But oaks
that don't they're not trees. They don't turn into trees.
Maybe they can, but in habitat they never get taller
than four feet max. Some stay two or three feet.
I mean, this is a pretty widespread phenomenon, especially in
North America.
Speaker 2: Right, that's right. So you got an well and if
you can done in Mexico, you see these beautiful shrubby
little oaks are quite prevalent. So, yeah, we often think
of oaks as being trees. But I don't know what
percentage of them are shrubs, but it is many. I mean,
you probably know Quercus minima or I'm trying to think
what these other little guys are, quirks cordifolia. These can
be shrubs like like ankle high or cap high. And
some of these species are chrisominous, right, some will really
spread clonally. There's a great article by Cornelius Muller nineteen
fifty one called the Significance of Vegetative Reproduction in Quircus.
He just goes through the natural history of a handful
of these things, Minima of Virginiana, Pyreneica, and Ilex in
the Old World.
Speaker 1: Quircus Havardia is another cool one. Another another cool scrub
oak from Yeah, this's from Monahans, Texas. Those cool sand
dunes out.
Speaker 2: There, absolutely and Hinkley.
Speaker 1: I yeah, yeah, yeah, HINKLEYI Jesus Christ, I've seen that
in habitat. That's unreal talk about a place to scene relict.
But I guess it can get upwards at like ten
or twelve feet tall in cultivation, you know, like Mike
Eason is doing it San Antonio Botanic Garden. But yeah,
when you see and set, they're two or three feet tall.
Speaker 2: One of the species I think is really interesting is
Quirkus prioides. So one of the most widespread eastern North
American species, Quircus neil and burget. It's called chinkapinoak, right,
and you find this thing. I don't know what exactly
its range is, but it's like, you know, we find
it in northern Illinois, maybe it's even in southern Wisconsin
down throughout almost all of eastern North America as a
tree growing on limestone or and calcarious soils. But then
its close relative is Quirkus prides, which is a shrub oak,
and is it grows as a shrub. Typically it grows
in sand soils, so not on limestone. It's distinguishable when
it's when it's sort of ideal, but there's like intermediates,
And it's unclear to me whether these things are you know,
two separate species, whether or not Prides actually something that
has arisen from ULMBERGII multiple times. The genomic data are
a little ambiguous, but we don't have a lot of
sampling on it. But yeah, I mean Priorities is the
one that is definitely like it's definitely a shrub. LAMBERGIAI
is definitely a tree.
Speaker 1: So why do these Why does some turn into trees
and some I mean not with just with this, but
with like a lot of especially in the West, a
lot of Quarkers species just stay low. I mean, I
guess there's is there something I mean for most of them,
they will stay low in cultivation too, right, Like that's
not like Kinkley where they'll get get turned into trees.
Like Quirkas Veccinifolia is always whether it's growing in a
garden setting or in the Klamath Mountains, is always going
to be a small three four foot tall shrug.
Speaker 2: Right, Yeah, well, I guess it's an. I guess it's an.
There's a certain like you find this too with quirks
a Lisipolia bear oak growing underneath like Quirkers Maryland because
of black jack oak, the black jack oak being the
tree solisifolia, the barre oak being the shrub and they've
each found a place in their habitat where they can
where they can survive. So I guess some of it
is niche differentiation. But then some of it too, is
that there's going to be selection in open environments for
a shrubby or habitat, I would think, but again I
don't know, I've never really Yeah, I.
Speaker 1: Guess that makes sense. Yeah, there's going to be selection
if it's really dry. Eventually, any individuals that get too
tall or will continue growing, I mean they just kind
of fall out because you don't Yeah, it's not a
beneficial Yeah. Yeah, it's costly and there's no benefit to
getting that big in a desert where the hot, dry
winds will just you know, take you apart. I want
to talk about plasticity and leaves because for identification purposes,
some of these are not easy, right, I mean, they
can be really tricky, and I'm sure for a lot
of people listening if they're out there trying to figure
out what the hell oak they're looking at, and they're
just looking at leaves, and it's not the flowering timing
or whatever. I mean, flowers aren't even really helpful in
a lot of oaks, I assume because they're so reduced
and simplified, like so many wind pollinated flowers. But leaf
plasticity is a real thing. I mean you can have
three different kinds of leaves on the same individual tree.
Speaker 2: Yeah, I mean, plasticity is really tricky. So when you're
it's it's like with aquatic plants, Like when you look
at aquatic plants too, super highly plastic. So when you're
studying a tree in the field, you really want to
study the leaves on all sides of the tree. You
go from the edge of the canopy to the inside
of the canopy, you will see the leaves change. If
that tree is cut down and sprouts from the stump,
you can get large, sort of amorphous looking leaves. So
what's governing plasticity, what's governing those leaf shapes. A lot
of it has to do with light environments, a lot
of it has to do with moisture, It has to
do with responses to insects. So all these things can
shaped and shape the leaf in ways that can be
that can make identification difficult. So it's really important if
you're learning the trees and stutting a tree to really
collect from a number of leaves and then look at
the whole population. Ask yourself, is this tree typical of
the population or is it just just an outlier because
it's growing in an odd area.
Speaker 1: Well, I think knowing that too is really helpful. Knowing
that with oaks, there's a lot of plasticity. You're gonna
have shade leaves, You're gonna have light you know, light
leaves that get more lights, you know, sun leaves. You're
gonna have juvenile leaves and adult leaves. There's a difference
in those, you know, I think it was a quirksagafolio
for instance. Well have really spiny young leaves which you
just wouldn't want to you know, they discourage your vivery obviously,
and then once they get more that, once they get
higher and more in the sun, they kind of round
out a little bit, or they can I think, I
guess looking at at the underside versus the top of
the leaf, to the texture, is it covered in indumentum,
that kind of thing is probably important too.
Speaker 2: It is, and it can be very very helpful. That
can be plastic as well, So some traits are less
plastic than others. But then but the outline is probably
the most plastic traits. So for instance, I when I'm
looking at queer because the lutina versus ellipsoidalys around here.
Usually you can tell from the leaves alone, and I'd
say like eighty ninety percent of the time, but there
are cases where I really want the end buds and
the acorns to be confident or look at the whole tree,
because you get you get clues from the bark, you
clues from the habitat. But yeah, that that plasticity is
super important though, because plasticity is part of what allows
trees to survive. They have to. Trees are stuck, they're
rooted in place. They like think of our quirkess PALMERI
like thirteen thousand years. It's been living there, as ice receded,
as the floor changed around it, as housing developed, developments
started to grow up in the hills around it. So
this is a this is a plant that's had to
put up with a lot, and if it weren't plastic,
it would have gone down. It can't go inside when
situations are nasty, it can't put on a rain coat.
It can't grab a water bottle. It's got to deal
with everything. And roots deal with this as well. The
root in the below ground environment is really heterogeneous. So
roots modify their growing habits, modify their anatomy as they
get into different areas of soil. So, yeah, that plasticity
is one of the one of the tree superpowers, and
oaks are super good.
Speaker 1: It's an adaptive trait, definitely. It's a beneficial trait in
terms of dealing with environmental stresses for sure. Yeah, that's right.
Do you're talking about roots, I mean all oaks are
Michael ryzel. I suppose there's none that associate with that
ectinomyce bacteria Frankia is there because I know other members
of the gaies there.
Speaker 2: Yeah, no, No, I believe they're all all just modified microhyzel.
Speaker 1: Ectomycro hyzol okay cool, And that of course is a
huge I mean being able to do that as a
huge benefit to none actually carry I mean the micro
hysil is just already in the soil. None actually carry
it with them in their acorn in any form.
Speaker 2: Huh No, not to my knowledge. I mean you do
find so when an acorn falls it falls with fungi
and fungi within it. So like then an acorn that's
developing will will sort of collect fungi from the leads
around it. There may be some vertical transmission from the
mob this I don't know for sure. I feel like
I read something. Jenna Urin has done real really cool
work on the on the endophitic fungi, this fungi that
live inside plants, and she did.
Speaker 3: An article on this one time.
Speaker 2: But anyway, so they pull, so they so they gathered
these fungi, and those fungi may help then may help
the acorn sort of fend off other fungi because then
when it drops to the ground, it's surrounded by a
whole new colony, a whole new community of fungi that
are living in the leaf litter, that are living in
the soil. And some of these are going to be
path pathogenic, right, They're going to harm the harm the acorn.
And having a robust community of and the phittic fungi
might be one way of fending those off.
Speaker 1: Right, I mean, just associating with micael rhizal fungi in
the soil especially, I mean, they're they have an interest too,
like they have an interest in their own self interest
in keeping the tree alive and preventing it from getting sick. Uh,
you know, protecting from other pathogenic fungi as well. I
mean it's one.
Speaker 2: Yeah, there's really great work being done by Luke McCormick
and by Peter Kennedy looking at the microizal fungal associates
at looking at the phenology the timing of those of
those microies of fungi growing, looking at the community structure
sort of which fungi are associating with which trees. But
no matter how you slice it, those microyes of fungi
are astutely essential to the to the to the success
of the tree because they go foraging for nutrients and
gain from the tree carbon in response.
Speaker 1: Is yeah, the swapping of ohk so really, I mean
this is a keystone genus. I mean, this is a
keystone plant and basically every every plant community they grow on,
I mean, they they feed a number of things, they
hold soil together, they harbor very beneficial fungi that are
that probably benefit a number of other trees in the
forest or scrubland that they're growing as well, especially if
you've got dwarf oaks growing on sand dunes like Corcasovardia.
You're holding, you're stabilizing dune communities for other plants. What
is do you know much about the There's a large
number of caterpillars, moth caterpillars that use oaks as a
host plant, and then of course those caterpillars later feedbirds,
et cetera. I perform a number of multitude of other
ecological services. Is that there's a I mean, what's up
with that? There's a there's a huge that's a huge
environmental niche for caterpillars that feed on oak leaves and
other things.
Speaker 2: Did right, So there's a few things going on that
I'm aware of, and there's this literature is much larger
than I'm than I know of. But we do know
that oaks harbor a disproportionate diversity of a number of caterpillars,
and that may have to do with sheer biomass. Might
be one reason when you look in North America and Mexico,
oaks have the most biomass, the most stuff being produced
of any of any tree genus. It might be partly
because of diversity. They offer a lot of chemical diversity
to caterpillars. And so we know, for instance, work that
Ian Pierce has been doing since two thousand and nine
and maybe even earlier has demonstrated that insects tend to
be the chewing insects tend to specialize on one clade
or another of oaks, so that tend to be red
oak clade specialists, that tend to be white oakclade specialists,
so that diversity of tree species and lineages may make
oaks disproportionately important to the insects.
Speaker 1: I didn't know there was a whole that I didn't
know there was a whole fido chemistry here that was
really important to some of these.
Speaker 2: There's a whole thing going on. And there's a great
trio of articles that Ian Pierce did in two thousand
and nine preceded the National Academy of Sciences twenty twelve
Evolution on the twenty fourteen paper, and preceeds the royal
piano goal to a royal Oh my bloodherds didn't just
be too anyway. These demonstrate that they look at the
at the leaf chemistry, and they demonstrate that the leaf
chemistry matters to the insects. But the evolutionary history seems
to even predict more of the leaf or bivery than
than the leaf chemicals themselves. So then so the insects
seem to be queuing in on this diversity. Now it's
not like they're doing malecosystematics. It's not like they're reading
the tree of life directly. So they must be queuing
in on the traits of the trees. But they are
traits that are that probably we haven't measured it yet.
Speaker 1: Or traits that are restricted to certain clades.
Speaker 2: Exactly, trades that are restricted to certain clades and that
we may not have measured yet.
Speaker 1: Yeah, God, that's yeah, that's so cool. This is is
such wild stuff to think about. And then there's a
lot of galls too, because I could California and Mexico
even here because Corcus Virginiana gets planted a lot on
here in South Texas in front of all these suburban
homes they build, which is crazy because Fuciformists is the
native one. It's more drought talent anyway. But but the
we get all these leaf galls in them, these little beads,
they look like little hardened marbles. Some of these galls
can be the size of baseballs in some species like
Carcus garyana out west in California.
Speaker 2: What's doing that super diversity? So the lions share these
galls and there's I want to say there's there's hundreds
of them. There's certainly over one hundred of them are
produced by a clade of wasps called the signipid wasps
and the snipid wasps I believe number about nine hundred
species worldwide. These are mostly oak specialists. And again great
work on this by a look at Graham Stones work,
really exciting work on the on the galls on Scott Egan.
Numerous people working on these gulls. But what they do
is the insects come along and they overposit into the tree.
So they've got an overpositors, that little stinger at the
back that is specially designed to get an egg into
the into the plant tissue. So what they'll do is
they'll overposit into the tree. When the egg gets in there,
this little wasp bag, it stimulates the tree to express
a certain subset of the tree zone genes. And that
subset of the genes that are expressed by the tree
in response to the signipid wasp bag produces the gall
and like you're saying. The gall can look like a bullet,
It can look like a gum drop, It can like
a pom pod, it can look like a like a
rubber ball, it can look like any variety of things.
Really cool, uh, cool diversity of galls that then serves
as a nest, a home for the for the wasp inside.
The wasp grows inside. Some of these galls will produce
exodates that are attracted to insects, so they will get
pulled away by ants and taken away from the tree
again to disperse the bays, get them into a safe
place to grow, and some of them will grow large,
like you were talking about, the ones that are the
size of a ping pong ball or so cut one
of these things open. What you'll find is that the
wasp is embedded way away in the middle, almost like
it's being protected, and it is being protected from parasites
from wasps that would like to parasitize. That's a niked wasp.
So there's a whole second set of wasps that parasitize
the sin wasps, which are themselves parasitizing the oak trees.
Speaker 1: So it's wild. This is so cool.
Speaker 2: It's a really cool sort of story that you ask
about like our oaks, keystone or foundational species. We think
of them often as more more foundational species. They totally are.
You get an ecosystem within an ecosystem, right within the acorn.
Within a single acorn, you get a fungal community, You
get weavils and moths that live on that that devour
the acorn. They will leave, and then sometimes there's a
group of ants that will move in after the weavels
have left it, or move in right alongside the weavels.
They'll they'll modify the acorn so that they have a
better place to live, the pack than pack the hole
that they entered in tighter so that only their their
own offspring can get in and out. Do you get
this ecosystem within ecosystems within ecosy They're so.
Speaker 1: Really, they're such important trees. It's I mean a lot
of people might assume, well, no one really, I say
a lot of people, I mean plant people. No one
really thinks about this stuff in general, are too obsessed
with trying to impress each other with meaningful material or
meaningless material goods. Excuse me, but it's my cynical take.
But a lot of people would think, Okay, when pollinated plant,
it's not gonna there's not going to be much benefit
to pollinators. But it's okay. I mean, they make up
for that in the multitude of ecological services they provide,
I mean tenfold. They're so massively important.
Speaker 2: If you want to be inspired about this stuff. Actually,
Doug Tellamy's book The Nature of Oaks, he really documents
a lot of these fascinating natural history stories and they're
really they really they're exciting. It's exciting. The more you
drilled into anything in the world, right, you find that
it's more and more interesting. There's more to find. But
that's certainly the case with.
Speaker 1: Yeah, he's a big booster for oaks. So is my
friend Andrew, Andrew the arborist. Yeah, big, big, Okay, they're
so cool. I mean, the thing that blows my mind
whenever I go to Mexico is the amount of diversity
in Mexico. It's insane. And you'll see oaks growing with
cacti like where you know, the kind of the lowlands
start to merge with the high you know, at the
right elevation and the right uh you know ecotone. But uh,
but why is there so much diversity in Mexico? Like,
why there's so many different oak species.
Speaker 2: I'm so glad you asked that i'd like to I
need to leave in about ten minutes if you don't mind,
Can we end with with Mexico oak diversity.
Speaker 1: That sounds good. I'm gonna get you again though here
just so you know.
Speaker 2: Okay, that I would love to. Okay, Okay, So the
Mexican So this is a really exciting story that came
out that I didn't understand when we started working on oaks.
I had no idea sort of what the order of
diversification was. It turns out that so oaks arise in
the Arctic, they move south ranchly over the course of
tens of millions of years from the early Eascene climatic
optimum temperatures are cooling, cooling, cooling. They really spread out
in the Americas, in Europe and East Asia and India
Oligosine you find all these lobes leaves showing up as
the temperatures drop precipitously, maybe twenty three million years ago.
Oaks get into Mexico twice, once in the white oak
clade section Quercus, once in the red oak clade Quercus
lobody and they do it about the same time as
temperatures are really drying and warming in the Miocene, they
sorry drying and cooling in the Biocene. They move on
down into Mexico, and it appears that in both groups
they move into the eastern Mexican mountains by way of
Texas right, so they move into the Sierra Madre Oriental,
they go down, they diversify in the trans Mexican volcanic belt,
send a little shoot down into southern Mexico, Central America,
and then they both moved back up the Sierra Madre
occidenttel the mountains on the western side and send a
few species up into Arizona, New Mexico and one even
over into California.
Speaker 1: This path, this is sorry, which is all.
Speaker 2: The way we're tracing. This is a wonderful, exciting integration
of field biology, natural history, and genomics. So we're able
to do this by going down working really working with
wonderful collaborators in Morelia, in Puebla, in Drongo in Tamilipis
to go do collections and then generate genome scale data.
So little slivers of DNA scattered across the twelve you know,
chromosomes of the oak genome, the roughly eighty million base
pairs of the oak genome, and getting little snippets of DNA,
and each one of those snippets tells us a little
story about the origin of a clade, about the differentiation
of a species, about the connection of that species to
its ecology. So by putting all these together, all these
data together, this is how we get this story.
Speaker 1: So just really good molecular work mixed with field biology.
Are you corroborating it with fossils at all? Are there
many fossils.
Speaker 2: Are now really bad? So I mentioned Thomas Dank near
the beginning of his talk. Thomas Dank and his colleague
Guido Grim and there are another colleague of theirs, Johannes Bouchal.
They've been wonderful collaborators, Marco Simoni as well from Italy.
They've been great and helping us connect the fossils to
the genomic data. And it's it's tricky because many of
these fossils. Thomas is brilliant at looking at fossil pollen,
extracting from its characters that help us say what clay
does issconnect to? And that's so important because a lot
of the fossils that we have are pollen. I almost
said merely pollen. They're pollen, And I hate to say
merely pollen because it's so so important. It is merely
pollen in the sense that it's so hard to find characteristics.
You know, you think how difficult it is to identify
an oak from its leaves. Imagine how difficult it is
to identify the oak from its pollen. God, but I
tell you it's well beyond me.
Speaker 1: You think about it. For a wind pollinated plant, though,
that's going to be probably a very abundant fossil compared
to say leaves or something, because they're just blowing it
out there bingo.
Speaker 2: Our oldest oak fossil is a is a set of
pollen grains known from Austria. It's along a little path
running past Saint Pancrat's Church that was deposited fortuitously fifty
six million years ago during this one hot hot period
at the boundary between the Paleocene and the u Scene
where temperatures spiked.
Speaker 1: I know about that.
Speaker 2: The PTM is do you know, it's like this one
hundred and fifty to two hundred thousand year period and
these pollen grains are found in that period, so we
know to like within two hundred thousand years when these
oaks grew. Now, those the first oaks in the world. No,
they can't be, because there must have they must have
had parents. But they're they're the oldest oaks we know.
And you know what's just to connect this back to
what's going on right now. The oaks are born during
the p ETM, when temperatures rose like as fast as
we've ever seen. If you look at the temperature as
I know you have the temperature curve for that period,
the PETM looks like a post driven into a hillside.
Temperatures are going up, and then in the PTM they.
Speaker 1: Soar and massive CO two, massive cor We're now plugging
CO two into.
Speaker 2: The atmosphere at a rate that absolutely dwarfs what was
going on.
Speaker 1: Oh, yeah, we're fucked, Okay, I wouldn't say that. Well,
it's it's gonna be an evolutionarily exciting time in the
next it's going to be a million years, in the
next million.
Speaker 2: Yeah, we are executing in experiments that has like it's
not like we have a natural analog. Our natural analog
is so much less dramatic than what we're doing. So, yeah,
we're and it's not clear to me, like when you
think about, like what's how Oak's going to respond, I
would give oaks a better shot than humans. Oaks have
been around for fifty six million years. Modern humans we've
been around for about to urn.
Speaker 1: Oh there's such fucking beasts. Oaks are such beasts. If
there's anything I mean before, but this podcast especially, I mean,
they've got so many tools in their toolbag of survival.
They're just they're they'll be fucking fine. Some might go extinct,
but they'll also.
Speaker 2: That's that's right, And that's that's the punchline I was
going to give is that despite that fact, like so
the background rate of extinction, if you just look at
the background rate of extinction, we should not be seeing
oaks go extinct. Maybe maybe every ten thousand years or so,
but like thirty percent of oaks right now are at
risk of extinction according the IUCN.
Speaker 1: Yeah, I was going to sugget that we're doing that.
Speaker 2: No, it suggests we're doing something wrong. So I think
we need to get our act together.
Speaker 1: Yeah we can. Yeah, Well, we're Civilization is like a
bad alcoholic. It's not going to change its behavior till
it hits rock bottom, you know. And we're getting and.
Speaker 2: It's not too late to slow the train. But we've
got to really be thoughtful about, like what kind of
world do we want this to look like? And what
are we willing to give up to have the nice
things that we we appreciate. I like being able to
drive to work if I feel like it. I like
reading the newspaper, you know, all the things that I
like living in a home, you know, But.
Speaker 1: What if you had a street car? What if you
could take a street car to work? Wouldn't that be nice?
Speaker 2: I'd be awfully I would be awfully happy.
Speaker 1: Yeah.
Speaker 2: Happy.
Speaker 1: Yeah. We're dealing with the crisis of a value system
that was doomed from its inception and it's finally what
it sowed.
Speaker 2: So we're going to have to for the sake of
all the things we're We're like, there's been a lot
of extinction that has allowed oaks to to take over
the continent, and thank heavens, but there's a difference this time,
which is like we're driving it, so so we have
a moral culpability that we need to get our hands
around and really make conscious, conscientious decisions about how we
live our lives societally and individually. And one of the
things that that we do know is that oak ecosystems
are highly diverse, and so we can do a lot
to restore and promote oak ecosystems and understand the oaks,
and it's one of the bajillion things we could do.
Speaker 1: So everybody should learn their local oaks and just grow
a shit ton of them and collect acorns. You start
start illegally planting acorns and public landscaping, vacant lots, railroad embankments, thoroughfares.
Speaker 2: Et cetera. I think getting involved in any kind of
any kind of ecosystem restoration, jump jump on it because
it's a great it's a great way to do something positive.
Speaker 1: That's what I would. Yeah, that's especially, but even just
collecting acorns in your pocket. Used to do that all
the time when I lived in California. We just collect
a shit ton and just sow, I'm here and there.
You know. I was like a little graffiti kid, just
planting acorns around wherever, just like the scrub jays do
out there. Because you get quirkisagrifol you're popping up all
over the train yard and you know, kind of run
down areas along fence lines where the scrub jays will
plant them and then forget where they cash them, et cetera.
So anybody could do that. If you're listening, do that.
Collect acorns, stash them in your pocket, just disperse them
all around. But I'm gonna get you back. I'm gonna
let you go, but I'm gonna we're gonna do a two. Okay, buddy,
in the next life.
Speaker 2: Life Am I allowed to plug a book?
Speaker 1: Well, yes, I wanted to ask you about that too.
Speaker 2: Yeah, I'm just going to recommend that. A lot of
what I'm telling is covered in a new book that
I've got coming out through University of Chicago Press. It's
called Oak Origins From Acorns to Species in the Tree
of Life. You can pre order it right now. It's
going to be out in December, and it really goes
through the story of oaks, from the acorns, from that
whole life history thing, natural history stuff that I that's
so exciting, through the tree of life to the genome.
And it's written to be readable. It's written I got
my background in this stuff, not by way of science.
I came in by way of being a naturalist and
teacher and enjoying being outside, and so it's really written
for I think of myself when I was twenty five
and I didn't know anything about evolutionary biology. So I
think these stories that we talked about are all covered
in that book.
Speaker 1: You're man, h That's what I got from this podcast.
You're a man of the people. You're you're an educator.
You're not you know, you're not just some elitist academic.
You're I mean, you could fit in with those crowds,
but you're very good at communicating teaching. I learned so
much in this and I already knew a lot. I mean,
this is like I didn't you know, it's you're teaching
me a lot.
Speaker 2: So and Joey, it's a. It's it's super it's a
it's a great honor to be to be asked to
speak with you today and speak.
Speaker 3: With your your group. So this is thank you, thank you.
Speaker 1: I'm just some who wiggled my way into this little.
Speaker 2: Way.
Speaker 1: But all right, man, well I'm serious though. We're going
to do a part two. I'll email you about it later.
I'll get the link for your book. I'll put that
in the description and uh we'll talk about Mexico and
the future evokes next podcast. Thank you so much for
coming on.
Speaker 2: Thank you to all right.
Speaker 1: You have a good day, Andrew. Everybody, I take care
of go Buck. Somebody