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Herbicides, Native Critters, and Us

Rainbows, Butterflies, and a Few Poisons

Praying Mantis

Praying Mantis

John and George today wandered Seabranch State Park the party-colored autumn wildflowers under heavenly heavens.  Funny what you ponder while playing in Mother Nature’s sandbox.  Today’s niggling thought was, “the flowers are spectaculous, but where are all the birds, bees, and butterflies?”  Now this may just be imagination or merely rosy historical re-creation, but compared with earlier life experience, butterflies and bees seem sparser.  Of course, “Silent Spring” documented Rachel Carson’s similar perception way back in 1962.  The Eagles were dying in ‘62, yet John and I think maybe we saw one far yonder today.  “Situation turned around,” we gloat.  Not so fast there Polyanna.

Katydid.  Todays' photos by John Bradford  (except maybe the butterfly.  Forgot who took that picture.)

Katydid. Today’s photos by John Bradford (except maybe the butterfly. Forgot who took that picture.)

Pretend there really has been decimation in the Hundred Acre Wood.  Who’d be surprised?  Assaults to wildlife are beyond obvious:  habitat loss, pesticides, climate change, and bioinvasion leap to mind.  The mounting evidence against the popular neonicotinoid insecticides such as imidacloprid (Merit) in bee Colony Collapse Disorder is getting harder to sweep under the carpet.  You don’t tug on Superman’s cape, you don’t spit into the wind, and you don’t dismiss lightly Harvard University research.  But today it’s herbicides, not insecticides.

Don’t weed-killing herbicides kill just plants?

Not necessarily.  Many herbicides have links to mammalian cancers, developmental deformities, endocrine disruptions, and more.  Many to this day are chlorinated hydrocarbons, the very chemical class Rachel Carson indicted convincingly before we shot a man to the moon.  The nation’s most-used weed killer, Atrazine, is a chlorinated pesticide in the water water everywhere.  This billion dollar baby is implicated in amphibian decline, not to mention data indicating human toxicity. Even in the drinking water?  You bet:  Right here in the Sunshine State:  CLICK.  And I take little comfort in the notion of,  “well, concentrations are low, so don’t sweat it.  Let the BRITA snag it and don’t tell the Tourism Bureau.”

Grizzled Mantid

Grizzled Mantid

Continuing with the big question, don’t weed killers murder just plants?  Answer 2.  Plants are the salad bar at the bottom of the food chain.  In that connection, a whole new herbicide familycalled sulfonylureas has crept up on us, although they are not widely known among the hoi polloi.  Examples include Manage, Manner, the cutely named Sedge Hammer, and many more with active ingredients ending in –sulfuron, such as halosulfuron.  These are touted as environmentally compatible, and may be the best of the SOB’s.  Sulfonylurea herbicides have two potentially troublesome attributes:  they are extremely water soluble, and they are jaw-droppingly deadly at snuffing plants.  Agricultural doses can be as low as grams per acre.   A little dab’ll do-ya.

So here’s the worry.  Super-water soluble suggests slippage into canals and aquifers, although breakdown is probably rapid, usually.  In the water AND lethal in minute quantities hand-in-hand wink at undermining microscopic plankton at the base of aquatic food chains.  I am not saying this is happening on a Chicken Little scale.  Just the opposite, you have to search under stones to find kindred neurotics.  Yet we fret.

Asclepias curtissii likes scrub.

This Milkweed likes scrub. Do Monarchs like it?

Even if the watery ecological pyramids have rock-solid bases, here’s a parting gift.  Monarch Butterflies are in decline.  Have you noticed?  Have you shrugged and muttered, “insecticides”?  An article in Scientific American this summer (online June 2014) collared a different suspect: the weed-killer Round-Up (glyphosate).  Monarchs breed on Milkweeds, predominantly in the U.S. Corn Belt.

The Corn Belt has been de-weeding itself with showers of Round-Up applied to crops Round-Up resistant GMO crops.  The regional weed purge has spared too few Milkweeds to sustain Monarchs as we knew them.

What a freakin’ pity.  Maybe it’s not just our imagination.

Where did the Milkweeds go?

Where did the Milkweeds go?

 
10 Comments

Posted by on October 17, 2014 in Herbicides

 

Bluestem Grasses

Andropogon (and Schizachyrium)

Poaceae

Today’s sunny fieldtrip took John and George through the north end of Seabranch State Park near Hobe Sound, Florida, the present epicenter of our green interests.  Today’s word to describe the glory of nature: Bluestem Grasses!

All Bluestem Grass photos today by John Bradford.

All Bluestem Grass photos today by John Bradford.

These are those large puffy-topped grasses, sometimes over 6 feet tall so pretty in October.  Always reluctant to pick favorites, apply tickle-torture and I may confess preference for those gorgeous wands of puff.  It isn’t just the silvery tops dancing in the breeze, but also the array of foliar colors.  So autumnal, a celebration of sunbeams and flickering memories, such as fond recollections of childhood strip mines.

I grew up in West Virginia immediately across the Ohio River from bigtime earth-rape.  Bluestems restore a tentative wisp of beauty to the toxic post-mining landscape.  (“Restoration,” yea sure.  Let’s go see the phosphate mines here in Florida.)  CLICK to see a Bluestem (“Broomsedge”) consoling an old mine crater in Illinois.

Bluestems make all the difference along roadsides, in old abandoned farm fields, along railroad tracks, and on rocky hilltops across much of North America and worldwide.  By the way, grouse like them.  Here is a Bluestem enhancing John’s path of life.

Several species coexist locally.  If you are nutty enough to try to sort them out, try our grassy web site.   Distinguishing these species can be extra-exasperating because:  1. The common species can be bewilderingly variable.  2. Different nearby regions house different species assortments.  3. Some hybridize.  4. They do not stick to their textbook habitats or to field-guide dimensions.  So for today, they’re just all “Bluestems.”

Andropogons usually have two bunny-ears.

Andropogons usually have two bunny-ears.

As hinted a moment ago, they tolerate the world’s worst soils:  graded roadsides, rocky hilltops, hellish railroad tracks, and scrub.  These rugged grasses have a few tricks, some of them studied in only one or few species.

Trick #1.  Some Bluestems have symbiotic root fungi (mycorrhizae) procuring phosphorus from shamefully nutrient-poor soils.

Trick #2.  Bluestems suppress potentially competing vegetation.  It is not mere competition.  Recent research shows some to diminish the “normal” nitrogen-fixing (fertilizer-providing) bacterial associates of non-grass species.

Grasses are turning out increasingly to have their own symbiotic arrangements with unconventional nitrogen-fixing bacteria.  Although data are sparse and preliminary, Bluestems sometimes have such unconventional nitrogen-fixers.  So could they sabotage the other guy’s nitrogen relations while enhancing their own, making the Bluestems kings of the starved soils?  Can they form a nitrogen monopoly?

Even weirder, one species preferentially takes up its soil nitrogen as ammonia, as opposed to slurping in nitrate, the other form in which plants take up nitrogen.  The selfish Bluestem is able to diminish soil nitrate to the detriment of potential competitors, while it somehow enhances soil ammonia for its personal private consumption.

Andropogon floridanus Jupiter Inlet Oct.

 
2 Comments

Posted by on October 11, 2014 in Bluestem Grass

 

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Feay’s Palafox

Palafoxia feayi

Asteraceae

Today John and George hotfooted it through the oven-baked Saharan scrub in Seabranch State Park near Pt. Salerno, Florida.  It was so torrid my shoes melted off my feet.  Really.  Ask John.  (Well, one fell apart.)  Recently a paved bicycle Autobahn made its way through the park.  The concrete ribbon is wide, flat, and dang sunny, and it offers passage through dozens of scrubbish species growing in isolated clumps recovering along the disturbed trail margins.  A unique “garden” view of Prairie-Clovers, Florida-Rosemarys, Golden Asters, and assorted grasses and sedges alone and uncrowded.  One of the finest species to behold is Feay’s Palafox, a member of the Aster Family.

Feay's Palafox.  All photos today by John Bradford.

Feay’s Palafox. All photos today by John Bradford.

William Feay (1804? – 1879) was a Savannah, Georgia, physician turned teacher with botanical instincts in the mid 19th Century.  During the Civil War Savannah Georgia was no place for a nice botanist.  He scooted to Florida, where he collected the original Feay’s Palafox specimen, conceivably abetted by another botanical M.D., Alvin Chapman, of Chapman’s Oak.  Just think, Feay’s Palafox is a souvenir of  the War Between the States.

Feay's Palafox

Feay’s Palafox

You don’t spend much time in scrub without seeing Feay’s Palafox, a slightly woody subshrub standing 2-8 or more feet tall with its showy white or pink flower heads.  Unlike most members of its family, the heads consist entirely of “disc” flowers, that is, the sort of flowers associated with the black center of a Sunflower head.  Our species hangs out in scrub or similar habitats, and seems to be fire-adapted.  Recent study show its strongest root-fungal symbioses to thrive after burning followed by decline during non-burned years, although the decline could be due to the recovery of competition.

What’s intriguing about Palafoxia is its circle of relatives.  We have three species in Florida: 1. Palafoxia texana,  a western species with a tiny weird toehold in the Florida Panhandle.  2. Palafoxia integrifolia, almost restricted to Florida.  And Palafoxia feayi, which is limited to Florida.

Feay's Palafox

Feay’s Palafox

The rest of the genus, about 9 additional species, are all more or less desert plants in the southwestern U.S. and Mexico.  This is reminiscent of Agaves, where we have two dubiously native species in Florida related to a big group in the Southwest, Mexico, and Caribbean.

That our local Palafoxia species live in Florida’s sandy scrub “desert” is no surprise then, given that they are far-flung offshoots of a posse at home in Death Valley and the Sonoran Desert.  Palafoxia supports a vision of Florida scrub as a now-isolated remnant of a once-contiguous Tex-Mex arid land stretching around the Gulf, eventually divvied up by changing conditions.  Similar Florida scrub-loving derelicts with Mexican roots include Scrub Jays and Gopher Tortoises.

If the Florida species of Palafoxia are spillovers from points west, do they represent one spill, or three separate splashes?  The latter:  Our three species are not closely related to each other.  Palafoxia texana stands aloof.   It does not even have the same number of chromosomes as our other two Florida species.  Likewise alone is Palafoxia integrifolia; as botanists who studied it said, it is “unquestionably the oddball of the genus Palafoxia,”  so odd, it used to be regarded as a separate genus.

Palafoxia integrifolia

Palafoxia integrifolia

Palafoxia feayi is allegedly most closely related to two species of the extreme Southwestern U.S., Mexico, and the Rio Grande Region.

How such an odd mixed up geographic pattern could come about boggles the brain.  One thing is certain, it dates back a long time, roughly (according to the botanists cited below) some 60 million years, before the continent-spanning genus fragmented into isolated lineages from Baja California to Seabranch State Park.

This all goes to reinforce nobody’s secret: Florida scrub is vastly older than other Florida habitats, with a history all its own.  When you walk in a Florida scrub, enjoy a little hint of the Tertiary Period when Mexico extended to Palm Beach,  when palm trees grew in Ohio, and when Gopher Tortoises raced Jackrabbits here from Chihuahua. (Apparently the tortoise won.)

——————-

Notes:

Most of today’s data and taxonomic assessments on Palafox come from B. L. Turner and M. I.  Morris, Systematics of Palafoxia (Asteraceae:  Helenieae).   Rhodora 78: 567-628. 1976.

Our two local species are easy to separate.  Palafoxia feayi is semi-woody, well over a yard tall, and has the flower heads surrounded by linear green or purplish bracts.    Palafoxia integrifolia is shorter than a yard tall; its bracts are more or less white, and narrowly elliptic.

 
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Posted by on October 3, 2014 in Feay's Palafox

 

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Witch’s Butter

Nostoc commune:  icky gross slime, or emerald carpet?

Cyanobacteria

Today John, George, and the Florida Association of Environmental Professionals Treasure Coast Chapter combed the wet regions of Jonathan Dickinson State Park for grassy plants.  About a million species to enjoy.  The pine woods vistas and wildflowers were gripping as always. Blue Curls were at their best.

Blue Curls by John Bradford.

Blue Curls by John Bradford.

Now look on the ground below that fetching wildflower, there’s something even better.  What grabbed me with the most gusto today were waves of green jello on the otherwise bare scrubby soil.  We’re talking about huge bacterial colonies of the  blue green bacterium (cyanobacterium) Nostoc commune.   Some observers erroneously call these blue-green “algae.”  And some get upset when the “algae” befoul their pristine lawn of pride.

Nostoc (by GR, John is drawn to beauty, but I like the lowdown and slimy)

Nostoc (by GR, John is drawn to beauty, but I like the lowdown and slimy)

This is one mighty germ.  It is photosynthetic growing in microscopic strings of cells in colonies as big as dinnerplates.  This species fixes nitrogen in special air-tight cells called heterocysts, seen as the larger light-colored cells in this photo link microscope view.

When you transform atmospheric nitrogen gas into forms plants can use, that’s fixed nitrogen.  Legumes and some other plants do it with the assistance of certain bacteria.   The symbiotic bacterial helpers in some cases, such as in Cycads, are species of NostocNostoc is the “algal” partner in some lichens as well, but today you have Nostoc living proudly off the leash.  If this nitrogen-fixing mat isn’t nitrogenizing the hungry scrub sand I’ll be a monkey’s uncle!

Nostoc in JD Park

Nostoc in JD Park

You could walk through the scrub for years in dry weather and never spy Nostoc, except maybe as an inconspicuous dry crust we crush while seeking interesting things.  This organism can dry out to a mere nothing for months, probably many years, and eventually bust out into its idea of glory when wet and ready.  Then dry times resume and bye bye for now.

The world is full of odd symbioses, and Nostocs (including today’s species? perhaps not) have an unusual relationship with a tiny midge prone to lay its eggs in the Nostoc jelly for a safe haven and nourishment.  What the fly offers the Nostoc is odd, if not adequately studied:  the larva seems to induce changes in colony shape with an enhanced grip on its substrate and probable enhanced photosynthetic production.  If I had nothing else to do, I could happily spend tomorrow searching for the larvae before the present Nostoc patches go back into hiding.  Want to go play golf tomorrow?  No thanks, I’d rather look for maggots in bacterial slime blobs.

Nostoc commune and related species are global and like arid places.  They tolerate blistering heat, arctic freezing, blazing sun, and extended drought.  No surprise they prompt research to probe the molecular biology behind happy life in extreme environments.   Nostocs make so much fatty gel they’ve raised the eyebrows of biofuelophiles.  They are so responsive to wet-dry cycles they cause research on environmental gene control.   Nostoc reacts to extreme sun exposure with a UV-screen not known in any other living thing.

That UV protection is perhaps linked to an example of why we don’t eat the weeds, even if other people do.  A recent article in the Journal of Ethnophamacology  described the traditional consumption of Nostoc commune in Peru.  Yummy good–but the fly in the ointment is a neurotoxic amino acid possibly linked to neurodegenerative disease.  There’s always something.

Maybe it is no surprise how these close relatives of the oldest fossils known on earth survive nasty conditions perhaps resembling the primitive Earth when cyanobacteria ruled.  Back when we were an almost-uninhabited planet.  Like Mars.

Hmmmm, too bad Mars is so dry these days.  Maybe a little green Martian Nostoc would come forth with a good honest wetting.

Mars Rover footprint, or John's tripod print?  You decide.

Mars Rover footprint, or John’s tripod print? You decide.

 
18 Comments

Posted by on September 27, 2014 in Nostoc commune

 

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Caesarweed

Caesar Weed

Urena lobata

Malvaceae

A joyous week of going native.  Tuesday evening it was fun to bore the West Palm Beach Chapter of the Florida Native Plant Society with my yada yada yada presentation, such an energized and cheerful group.  Then this morning John and I joined ecologist Arnaud Roux for a sunny slog through Jonathan Dickinson State Park soggy shores to prepare an upcoming professional workshop on grassy plants.  We enjoyed the Blue Curls, Roselings, Chaffheads, Liatris and so much more as pretty as a state park brochure.

The pink "mini-Hibiscus" flower (by John Bradford).

The pink “mini-Hibiscus” flower (by John Bradford).

So many lovely native wildflowers, so let’s talk about a Category I invasive exotic weed stuck in your socks.  You don’t live in Florida long before meeting Caesarweed.  Even if you never encountered its pink “Hibiscus” flower, its burrs have encountered you.  The sock-stickers are segments of the fruit, which comes apart like slices of VELCRO pie.  They arrive home in your pants cuff, liberate themselves in the Maytag, and transfer amusingly to your wife’s apparel.

VELCRO pie.  By Top Tropicals (permitted use)

VELCRO pie. By Top Tropicals (permitted use)

Clinging may help explain the enormous range of this around-the-world weed of unclear origins, possibly in or around Tropical Asia.  Florida has been home since at least the 1800s.  Like many weeds, Caesarweed enjoys the company of humans as we create disturbed habitats, disperse its bristly hitchhikers in our spouse’s delicates, and enjoy its useful attributes.

As with so many widespread plants, the traditional medicinal uses are too many to list and actually a bit boring, although if you suffer “windy colic,” forget that medicinal marijuana, this is the weed for you.

Horticulturists are familiar with urease as an enzyme in soil microbes critical for transforming the natural decay product (or commercial fertilizer) urea into plant-useful ammonia/ammonium.   You can buy “urease inhibitors” to ration the conversion.

NitroGainUI-logoR

Caesarweed has urease in its seeds, clearly giving them a kickstart at germination time.  Urease-enhanced plant seeds are not rare, but even so, I dig the idea of a powerweed equipped with its own fertilizer-making enzyme.  So often weeds have special means of establishment after their relocational skills plop them in strange new worlds.

Speaking of special adaptations, flip over a Caesarweed leaf.  At the base on the main veins are glands, apparently to feed protective ants.

The leaf glands.  Apologies for the crummy focus. Don't blame John...my bad.

The leaf glands. Apologies for the crummy focus. Don’t blame John…my bad.

Beyond historical and modern medicinal interests, humans cultivate Caesarweed for fibers up to a yard long.    Not a huge surprise really, as the Hibiscus Family is a fibery bunch: Cotton, Kenaf,“Indian Hemp,” and more.  While some parts of the world are trying to figure out how to discourage Caesarweed’s growth, others research ways to boost germination rates and enhance growth as a commercial crop, especially in Africa where the plant acquires the name Congo Jute.  Before synthetics, Florida used to be a fiber growing and testing center.  It would be fun to know if Casaerweed had any participation in that.

 
10 Comments

Posted by on September 19, 2014 in Caesar Weed

 

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In a Lather Over Sudsy Snakewood

Asiatic Snakewood

Colubrina asiatica

Rhamnaceae

As John and George go about our Friday botany biz, sometimes near the sea—especially in the Hobe Sound Wildlife Refuge—we trip over an odd and different-looking woody plant known as Asiatic Snakewood.  Although a small number of native species of Colubrina live in southern-most Florida, our local Colubrina is Asiatic Snakewood, an invasive exotic stinker, but an interesting stinker.  It thrives in some coastal strand habitats, crowding rudely into hammocks and mangrove areas.   Every invasive has its tricks, and one of those earns Snakewood its name; the stems reportedly grow over 30 feet per year, snaking around, rooting where they touch the soil.  It’s really no fun ranting about the invasion,  so for now let’s try to know thy Snakewood.

Snakewood at Hobe Sound.  Today's photos by John Bradford.

Snakewood at Hobe Sound. Today’s photos by John Bradford.

Inquiring minds might ask how it got from its presumed origins around Tropical Asia to the Hobe Sound Wildlife Refuge nature trail.  Two main possibilities stand out (a combo of the two seems likely).

  1. Maybe humans brung it, at least to the Caribbean in the 9th Century or before.
  2. Maybe the seeds floated or came by bird delivery.

Colubrina Close JB

To look at possibility # 2 first, this species gets around!  Let’s say it originated in Tropical Asia, yet it is regarded as native in Hawaii, and decorates the tropical world from Africa to Australia and beyond.  The seed journey begins when the fruit explodes.  Pop.  The seeds like to float in saltwater.  A skeptic might now wonder, “well, if it migrates aggressively, perhaps it managed to get around all the way to the Caribbean and Florida on its own.  Wouldn’t it then be native, technically speaking?”   (And of course Global Warming could lend a hand.)  We’re unlikely to see anyone make that case.  I think we can all agree human activity probably had something to do with it. (Or then again, maybe you disagree.)

Which brings us to arrival scenario #1 (we’ll conveniently ignore many other human-mediated but inadvertent and boring possibilities).  To appreciate possibility #1, a little background is relevant.  Snakewood has a laundry list of traditional medicinal applications, and those long snake-sticks can be woven.  The species is chock-full of bioactive chemicals, the most famous being what are known as saponins.  Saponins are widespread in the plant world, and some plants make a lot.  Another name for Colubrina asiatica is “Latherleaf,” because saponins froth in water, and our species is sapono-tastic.  The sudsiness has served humankind, and there’s another benefit: saponins snuff fish.  A multi-use weed!  You can take a little Colubrina down to the river, launder your drawers and enjoy a seafood lunch.

 
6 Comments

Posted by on September 13, 2014 in Asiatic Snakewood

 

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Chapman’s Oak

Chapman’s Oak

Quercus chapmanii

Fagaceae

On Friday John and George explored a corner of Seabranch State Park near Port Salerno, Florida, previously unpenetrated by us, a big area of scrub more mature with larger Oaks and Pines than many other local scrub areas.

The Prairie Clover (Dalea feayi) was pleasingly in bloom.

Feay's Prairie Clover Friday 9/5/14.  All photos today by John Bradford.

Feay’s Prairie Clover Friday 9/5/14. All photos today by John Bradford.

 

The Yellow Garden Spider was enjoying the day.

What's a tuffet?

What’s a tuffet?

 

If we’re going to feature Chapman’s Oak, we better establish who was Chapman?  Alvin Wentworth Chapman (1809-1899) witnessed most of the 19th Century, remaining active to age 90.  He was a physician and founder of modern Florida botany.  Back then doctoring and botany often occupied the same soul.  (Come to think of it,  my own father was a physician-and part-time naturalist.)

Chapman's Oak

Chapman’s Oak

 

I believe many species distinctions we use in modern manuals date back to Dr. Chapman’s antebellum (1860) Flora of the Southern United States, setting up subsequent generations of addition and refinement in 20th Century floras.  Originally from Massachusetts and a Union sympathizer in the Civil War, Chapman lived most of his long productive life isolated in Apalachicola.

Most local scrub areas host Chapman’s Oak, and in Seabranch State Park this species is abundant, in fruit, big by local standards, and striking with two special eye-catching features:

Feature #1:  Galls as big as ping pong balls and as red as apples, before turning brown.

Gally-gee---they resemble apples

Gally-gee—they resemble apples

 

Eye-catcher #2:  Super-glossy-reflective leaves.  Chapman’s Oak has some of the larger leaf blades found in the sun-drenched scrub habitat where the general tendency in most plants is toward reduced leaf sizes.  You’d think those big Chapman solar panels might cook and dehydrate in the scrubby sunbath, and we’ll see in a moment that to be the case in a limited way, but I’d like to think that reflective surface offers protection.  We usually think of big leaf blades as typical of shade, so maybe Chapman’s Oak straddles the best of both worlds:  expansive blades for life in a mature scrub under the shade of Pines, and at the same time protected when un-shaded.  This is mere speculation—the prerogative of the individual who types the blog.

Chapman's Oak leaves and acorn

Chapman’s Oak leaves and acorn

 

Several species of Oaks grace our local scrubs, and they are an interesting committee.  We won’t sort out here how to tell them apart (for help see Lesson 3 in our online class), but some general remarks may interest a reader or two.

Would you expect a cluster of Oak species living in the same habitat in the same place to be closely related?  They are mostly just the opposite—a highly disparate group all thrust together.  Think of a bunch of new neighbors getting acquainted around the pool in a recently built Florida condo complex (perhaps built where scrub once was).  The first conversation topic over frosty Coronas at the meet & greet is, “where are you from?” —- “We’re from Syracuse,”  “I came here from Philadelphia,”  “Minneapolis,”  “Argentina,” etc.    Same thing with the Florida scrub-dwelling Oaks.  They all came to Seabranch State Park from different directions, different relationships, different histories.  How’d they all get together in the same scrubby sandbox?  Fairly remarkable, so Floridian, and just like human Floridian transplants, they have their own subtle climate preferences, especially with respect to differences in soil water on that scrubby sugar sand.  We’ll return to that.

You can divide the local Oaks into three distinct species alliances, the Red Oaks, the White Oaks, and the Live Oaks.

Representing the Live Oak species group, in Seabranch, we met Sand Live Oak (Quercus geminata) and Dwarf Live Oak (Q. minima).  From the Red Oak Guild was pretty Myrtle Oak (Q. myrtifolia).  Chapman’s Oak alone hails from the White Oak gang.

Today it is all about Chapman’s Oak.  Wonder why it is so rare in cultivation?  Apart from any necessary symbiotic microbial partners, its soil moisture preference is under 7%!  (Sand Live Oak, by comparison which is cultivated prefers over 12%.)  Chapman’s Oak, perhaps by dint of longevity, can extract water from fairly deep scrub soil, recorded down to over 6 feet.  It initiates leaves during the early rains of Spring, having them in place during the long hot summer and early autumn.  As the dry season rolls around, Chapman’s Oak is particularly prone to have those oversized leaves dehydrate internally…drier than any of several scrub species measured.   Remember our worries above how big leaves may dry out.  They seem to, to a point, but under protected control, on schedule, and basically okay.  Mother N watches over her Oaks.

Chapman’s nearest relative, as revealed by DNA, is the so-called Bastard White Oak (Q. austrina).  BWO inhabits more-northern Florida and beyond on soil with more moisture.  In short, you might interpret Chapman’s Oak as a heat-seekin’ dry-lovin’ derivative of its bastard northern cousin.

——————————————————————————————-

Note:  Technical data largely from article by J.  Cavender-Bares and collaborators.  Phylogenetic Overdispersion in Floridian Oak Communities. Am. Naturalist 163:  823-843. 2004.

 
6 Comments

Posted by on September 7, 2014 in Chapman's Oak

 

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