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About George Rogers

Florida botanist

Bluestem Grasses – Andropogons

29 Oct

Bluestem Grass

Andropogon, several species

Poaceae

Hurricane Sandy and Hurricane Work Obligations thwarted the usual Friday trip this week.  A little alter in time, this morning dawned cold and brightly sunny, and I visited the Sweetbay Natural Area near the Palm Beach North County Airport.  One of John’s and my favorite wet sites with a civilized paved sidewalk.  The cold was compensated by the striking beauty of the horizontal sunbeams lighting up the silvery beards on the various Bluestem (Andropogon and Schizachyrium) grasses.  Those fireworks alone justify an early start.

Splitbeard Bluestem with its split beard (don’t recall who took the pic)

It is not my purpose now to be schoolin’ ya about how to distinguish the Andropogon species.  John and I tried that, and the results are a click away at  floridagrasses.org.

Some readers might agree that locally the Bluestem Grasses can be tough to differentiate.  Whenever you see reference to a “species complex,” watch out for a puzzling network of funny business.   Most of our nearby species belong to the “Andropogon virginicus complex,”  which seems to be diploid, comparatively free of apparent hybridization, and yet often with subtle visible differences between species.

One of the prettiest and most distinctive species is the Splitbeard Bluestem, Andropogon ternarius, which is a tetraploid (has 4 sets of chromosomes) and has a particularly delicate appearance:  tall and slender with big long silvery-white bunny ears (spikelet clusters) displayed on wirelike wands.  It looks like a work of art, and  I always enjoy encountering this exquisite bit of creation.  Gardeners agree.  I recently saw this species for sale at approximately $40 per cell tray.  A seedy variant developed in Florida chiefly for habitat restoration is called “Ft. Cooper.”

The plant world is full of fluffy-puffy feathery wind-dispersal units, but Andropogons are  the ZZTops of the flora.  In fact the name Andropogon means dude with a beard.

You could scarcely design a species more appropriate to wind-dispersal.  The bunny ears bust apart at the slightest whisper, separating into parachute-bearing “seeds” (spikelet clusters) to blow hither and thither.  The microscope view shows what they bust apart into.   The feathery parachute hairs in the photo are of obvious function.  The two long threads (awns) visible in the picture are less obviously useful.  The awns probably catch the wind or bump against adjacent plants and help the bunny ears bust apart.   Also interesting are the two small vertical “daggers” you see flanking the main spikelet.  Those are sterile (seedless) spikelets.    Who knows—maybe they’ve lost their function but the genes that make them have not quit altogether, sort of like the human canine teeth.

Andropogon ternarius spikelet cluster. Center-left is large fertilie spikelet with long awn. Smaller sterile spikelet “dagger” is vertical just center-right. Another awn is visible tilted to the right.

The natural distribution of Andropogon ternarius is roughly the southeastern 1/3 of the US from Florida to New Jersey, Indiana, and Texas.   At least that was where it was is was yesterday.   Sandy may redistribute some bunny ears today.

Split-bearded dudes

 
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Posted by on October 29, 2012 in Bluestem Grass

 

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Bay Bean

20 Oct

Baybean

Canavalia rosea

Fabaceae

Bay bean flowers in front of sea grape leaves (by JB)

Today John and George played hooky in the coastal dune-hammock strand on Hutchinson Island at Beachwalk-Pasley.   This restored strip is a living museum of maritime species.  The treat is seeing all together in glorious flower at once:  Bay-Cedar, Bloodberry, Buttonwood, Corky Stem Passion Vine, Cowpea, Crownbeard, Fiddlewood, Native Lantana, Marlberry, Nickerbean, Purple Morning Glory, Railroad Vine, Sea-Rocket, and more.  The star fruit-laden species were Sea-Grapes and Fiddlewoods.  The most magnificent display was the Baybean, trailing on the ground, festooned over upright plants, and dangling from overhead limbs like a party decoration.  Flowers, fruits, seeds—the whole works.

Dangling Canavalia pods (by JB)

Baybean beans are easy to spot with their blotchy surface pattern.  To me they look like engorged ticks on a dog’s neck.

The dangling pods are the size of a flattened sausage, and made of tough stuff. The big pea-type flowers are a rich rose color.   You can find on-line reports of the blossoms drugging their pollinators, but I’m skeptical of that.  (Would be fun to investigate though.) Something bay-beany with a bigger blog presence is smoking the big tough fibrous  Canavalia pods or leaves for a “Woodstock” experience.  Sometimes they are in the false marijuama sold as “bath salts.” The blog world has lots of of chatter on this topic, yet they all seem to miss one minor point: YOU’D HAVE TO BE CRAZY!?!

Here is why I would never ever ingest Canavalia in any format: I enjoy life.   Canavalia is the namesake of one of the world’s most fascinating poisons, canavanine.  Canavanine occurs in Canavalia, although I do not know about C. rosea specifically.  It is present in other pants too, such as alfalfa.

Here is how canavanine works.  It is wickedly insidious, and pardon the Biochemistry 101. Living things are all about proteins.   Proteins have precise structures and precise functions.  Proteins are chains of amino acids, just like sentences are chains of words.  Alter an amino acid, and you have the effects of a mutation, not good.   An amino acid impotant in protein building is arginine.  You can buy it in the health food store.  Now here is the important point—Canavanine resembles arginine.  Canavanine sabotages proteins by becoming built into them disguised as arginine.  This is the equivalent of saboteurs secretly replacing ball bearings with rubber balls in the airplane factory.  Kaboom!  Put THAT in your pipe and smoke it.

[Note: The chemical structures come from the Universite Pierre & Marie Curie, Paris]

 
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Posted by on October 20, 2012 in Baybean

 

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Cowbane, drying out in the marsh

14 Oct

Cowbane

Tiedemannia filiformis (Oxypolis filiformis)

Apiaceae (Umbelliferae)

Northern transplants like myself recall Queen Anne’s Lace (Daucus carota)—actually an Old World weed and the ancestral species of the modern carrot—in childhood meadow memories involving bug nets.  Every time I see Water Cowbane my brain sees Queen Anne’s Lace.  They are related in the Carrot Family.  Water Cowbane lives in marshes and along wet shores throughout Florida and beyond.  John and George enjoyed it in its full flowering glory Friday along the marshy nature trails in the PB County Solid Waste Authority “wilderness.”

Cowbane with Black Swallowtail caterpillars (JB)

Beware “bane” in a plant name (Henbane, Dogbane, Horsebane, Bugbane, Fleabane); it is a sign of poison, and Cowbanes have in fact poisoned cattle.  Despite grocery store members, such as celery, and several spices and herbs, the Carrot Family often tends to be dangerously toxic, including Water Hemlock (Cicuta), Poison-Hemlock (Conium), and additional nasties.

Cowbane (JB)

It is unclear to what extent the toxins enter and protect the Black Swallowtail Butterfly caterpillar, which favors the Carrot Family in general, and locally this species as host plants.  The caterpillar, which can disable the toxins, develops a false “snakes tongue” as its personal scarecrow.  You might say it is a bird-bane.

Water Cowbane has abnormal  leaves shaped like thick knitting needles.  The proper term for organs with this shape is “terete.”

Knitting needle leaves

Now  here is the punchline, so listen up:  terete leaves (or similar photosynthetic terete stems) occur in many unrelated plants in marshy or boggy habitats.  In other words, among plants of open sunny marshes there is convergent evolution leading to narrow cylindric leaves.  I won’t bore you with a list of examples here, but some are in the notes below.

Looking beyond wetland plants, where else do you encounter terete leaves or round photosynthetic stems?  In deserts,  such as the African Spear Sansevieria familiar to gardeners.  This makes sense, since a terete leaf (or a round photosynthetic stem) has a comparatively low surface area relative to internal tissues, thus reducing water loss and sun exposure.  Another dry place is perched up epiphytically where water isperiodically hard to come by.  Here too we see terete leaves, such as those on some Vanda Orchids.  Salty habitats are “dry,” and  our local Sea-Puslane has more or less terete leaves.  Right—that all makes sense, but . . .

How could it be that plants sitting directly in water have “desert” –style terete  leaves or similar stems?  Back in the year the Wright Brothers flew (1903) botanist Rosina Rennert wrote a detailed monograph on precisely this topic featuring the Water Cowbanes as a “Swamp Xerophyte.”  She is not by any means the only biologist to develop the idea of aquatic habitats being “dry” to plants; she just focused the spotlight brightly on today’s species.

At Jonathan Dickinson State Park, 11/13/15 by John Bradford

At Jonathan Dickinson State Park, 11/13/15 by John Bradford

I am not up on the relevant contemporary plant physiology, but going about my routine botanical business from time to time I run across repeated reasons explaining how marsh life can be “dry” to a plant.  Most obviously a marsh can be relentlessly sunny, and it can dry out periodically, toggling from a wetland to a “desert.”  Additionally, roots need oxygen to function properly,  and a plant rooted in stinking no-oxygen mud may have trouble with root functions. And third, the water chemistry of some wetland settings impedes water uptake.     Some wetland species vary the form of their leaves dramatically in response to different water and soil conditions.  It would be interesting 109 years later to resume Rosina Rennert’s experiments doing that.  I wonder what Rosina thought of Wilbur and Orville’s flying machine.

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Notes: Unrelated plants with knitting needle leaves:  Some Rushes (such as Juncus scirpoides), some Grasses (such as Panicum tenerum, Paspalum monostachyum), and some Sedges (Eleocharis interstincta,  Cyperus articulatus, in both species the photosynthetic stem is the terete organ), some Arrowheads (Sagittaria teres), and Quillworts (Isoetes flaccida).

 
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Posted by on October 14, 2012 in Cowbane

 

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Floating Ferns, Ammunition, Fertilizer, Cow Dung Slurry, and Eggbeaters

07 Oct

Azolla filiculoides and additional species

Salvinia minima and more

This week’s Friday trip was displaced by a scintillating department chair meeting, two life-wasting hours dedicated to e-mailable calendar events, futile parking space rants, program enrollment statistics, personal horn-tooting, and oh-so-witty repartee.  My seat-neighbors survived with sneaky smart phone activity.  My phone is dumb, so I just stared out the window sullenly, dreaming of native plants and chicken marsala, and wondering what was floating on the polluted drainage ditch across the parking lot.

Upon adjournment, I checked out the ditch and found the pond scum to be largely fertilizer-fed Blue-Green Bacteria (Blue-Green “Algae”), and, better, there were little floating ferns, always fun to see. (They have their own Cyanobacteria, so stay tuned.)

In Florida we have two genera of small floating ferns:  Azolla and Salvinia.  Each has two Florida species, more or less, with room for debate on exactly which species are present, how they are defined, and exactly where they are native.  Let’s not get into all that in our fun little blog, except to mention that the ancient Old World rice paddy species Azolla pinnata seems to have made its Florida debut right here in Palm Beach County.

Both Salvinia and Azolla float with an option of settling onto wet mud when waters recede.  Both are abundant in local waters.  Both come and go, almost magically, and have the capacity to go forth and multiply—to the extent of utterly covering the water surface, or clogging irrigation pumps.

Sometimes called “Waterferns” or “Mosquito Ferns,” Azollas are the smaller-statured  of the two.  You could mistake them at first glance for Duckweeds (that’s a different blog).  A single Azolla plant can be the size of a coin, floating on the water surface with tiny branches bearing tinier leaves overlapping like shingles.  Each plant has a roughly circular irregular and lumpy outline.  (Azolla pinnata has an outline like a squashed conifer tree.)   They can form small roots, with the absorptive root function supplemented by thin-walled hairs on the leaf surfaces.

Azolla filiculoides (by JB?)

Azolla consorts in a symbiotic relationship with Cyanobacteria (often misnomered “Blue-Green Algae”) able to fix nitrogen, that is, transform atmospheric nitrogen into fertilizer.  (The German chemist Fritz Haber won a Nobel Prize in 1918 for figuring out how to do this industrially to make fertilizer and to make  ammunition.)  The symbiotic Cyanobacterium, Anabaena azollae, is impotent in the presence of oxygen, so the fern gives its little friends climate-controlled mucilage-lined gas chambers in hollow cavities in the leaves.  Anyone with a microscope can break the fern apart with a needle in a drop of water and see the Anabaena dramatically.

Anabaena liberated from Azolla (by Grupo Biologia Alicantina)

Lots of plant, fungus, and animal species have one-on-one symbiotic relationships with microbes.  Inquiring minds might wonder  what happens to the intimate relationship when the host undergoes its sexual cycle.  How do the host babies wind up with their own microbe?  Different  strokes for different folks, in Azolla the bacterium rides through the fern’s entire reproductive cycle.  Ain’t that somethin’!  Each baby Azolla has Anabaena as its birthright, sort of a trust fund baby.

Azolla leaf with Anabaena in gas chamber (from J. Plant Physiology 166. 2009)

A floating fern that can make fertilizer is a handy asset in a rice paddy, and Azolla has been boosting since ancient times.  That’s why Azolla pinnata is sort of interesting here, even if invasive.  Did it follow rice cultivation to the Agricultural Area, or just show up on its own accord? (You can imagine 100 ways for it to arrive.)

Salvinias are sometimes called Water Spangles.  Our widespread Water Spangle is the Invasive Exotic Salvinia minima, perhaps enjoying a little Global Warming and inching northward.  This Tropical American native has spawned reports across the southern U.S. with cameo appearances in northern states.  (Taxonomic-nomenclatural confusion and easy mobility complicate assessment of the exact distribution.)  It can turn a canal into a green lawn, as I saw recently in Riverbend Park in Jupiter.

Salvinia minima (by JB?)

Salvinia is easy to recognize.  The leaves are in whorls of three.  Two leaves are identical, nearly circular in outline, about a centimeter in diameter. (The leaves are larger in S. molesta , which has a couple reports in Florida, but not in our haunts so far.)  The third leaf in the whorl looks like a brushy branchy root dangling in the water.  The two round green leaves have unwettable surfaces with extreme hairs.  In S. minima the hairs look like a scary Halloween tree; in S. molesta the hairs look like an eggbeater.

Scary Salvinia minima hairs (by Visual Photos.com)

Don’t look for spores as encountered under the fronds in most ferns.  Both Azolla and Salvinia have a special adaptation to the boating life— spores in little hard cases called “sporocarps.”

I have a personal theory that pond scum is going to save the world.  What grows faster?  Scarfs up pollutants in the process?  And utilizes bad carbon dioxide?  We’re talking biofuels, and even food.  This video will give an idea how fast Azolla can grow —just toss in a little cow dung slurry—and feed the world! (Or at least feed the livestock.)  CLICK

 
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Posted by on October 7, 2012 in Floating Ferns

 

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Sonicatin’ in the Meadow

30 Sep

Meadowbeauty

Rhexia cubensis (and additional species)

Melastomataceae

When it comes to meadow flowers, the fairest of them all are Meadow Beauties (species of Rhexia), with their delicate pinky-lavender, or less often white or yellow flowers.  Do beauties in the meadow resemble the big Tibouchinas in the garden?  Yes, they’re all family, the Melastomataceae, along with Tetrazygia bicolor (misnomered West Indian “Lilac”) a popular shrub in native plant gardens.  Melastomataceae have elegantly curved leaf veins, and have unique oversized yellow curved anthers. (Anthers are the pollen-producing flower organs.)

Image

About 10 species of Rhexia reside in Florida, representing the lion’s share of this 13-species genus mostly confined to the U.S. with minor extensions into Canada and the West Indies.  Rhexias rise up after disturbance and can spread vegetatively.  Some have tubers and/or creeping horizontal roots pretending to be rhizomes.

In our immediate zone of exploration, Rhexia nuttallii is the only species that has its anthers in a radially symmetrical arrangement at the flower center.  In the other species the anthers are longer and in a lopsided bilaterally symmetrical arrangement.  Rhexia cubensis has glands on the stem hair tips and particularly bristly fruits in contrast with glandless hairs in R. mariana and less-bristly fruits.  Rhexia nashii too has the stem hairs glandless, and differs from R. mariana by having non-bristly (or nearly so) fruits.

Do you find these beauties to be sometimes hard to identify? They vary; for instance, Rhexia cubensis has diploid, tetraploid, and hexaploid strains.  (This refers to chromosomes in pairs, or sets of four, or sets of six.) Some species hybridize.  Rhexia mariana is especially known for mixing it up with its kin.

The anthers are bright yellow, presumably as snazzy come-ons for bees, yellow suggesting yummy pollen.  There is a little controversy around that topic.  Yet yellow decoration of bee flowers is widespread, and the bee-draw of yellow on flowers is generally accepted.  (And suggests some fun experiments.)  Certain Melastomataceae have two types of anthers:  big yellow advertising anthers along with smaller, drab-colored “business” anthers to dust the bee visitors with pollen.  If dual-anther types exist in Rhexia I’m not aware of it.  How they do function in Rhexia is fascinating, however.  So read on:

They employ “buzz pollination,”  a phenomenon found in about 8% of flowering plants dispersed among unrelated families—thus a great example of convergent evolution.  Many members of the Potato Family, Solanaceae, feature buzz pollination, and now back to Rhexia.  Most pollination research has involved Rhexia virginiana, which is absent around here, so we’re extrapolating recklessly to our local species.

Those big, elongate, curved anthers draw bees seeking pollen as an important baby-bee protein source.   In most non-buzz flowers the anthers open, wads of pollen spill forth, bees get dusted, and off they go.  But that is a crude approach vulnerable to bee greed, wrong pollinators,  bad timing, and weather.  In Rhexia and other buzz flowers the anther has a single pore at the tip.  The pollen remains safely inside the anther until good vibrations puff some pollen out pore.  Not just any bee can get a buzz on.  Forget honeybees.  Bumblebees do the job, and so do multiple additional types of native bees.  A fancy term for buzz action is sonicating.

Enjoy  simulated sonication here: BUZZ

Now this is just pure speculation, but don’t those anthers shaped like a bent bottle with an expanded chamber at the base and a narrow neck look like guitars where the music box “amplifies” the buzz?  In some Rhexias the anthers change color on their second day.  Interestingly, the vase shape of the anthers repeats in the fruit, which likewise has a swollen base and narrow neck, dispersing the tiny “cochleate” (snail-curled) seeds.  As in so many other wetland plants, the tiny seeds have sculptured surfaces.

The buzz system rations pollen.  In Rhexia (virginica) only 10.2 % shakes forth per visit. Thus to complete its load a buzzy-bee is compelled to move along, and plenty of pollen remains behind for other bees on other days, extending the effective life of the flower.

[The photo is R. cubensis, by John Bradford.]

 
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Posted by on September 30, 2012 in Meadowbeauty

 

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Native Agave Species, Probably Not Native and Perhaps Not Even Species

23 Sep

Agave sisalana

Agave decipiens

Agave neglecta

John and George this week indulged their multi-week fixation on the Savannas Preserve State Park and neighboring scrublands.  Yesterday we were working on the railroad all the live-long day.  Railroad tracks are interesting botanically, because the rights-of-way have been there a long time as unintended plant refuges, and because choo-choos spread species.   The floral beauty this week is stunning with yellows coming from Goldenrods, Crotalarias (not necessarily native), and weird little Neptunia.  Butterfly Pea (Centrosema virginiana) was so abundant and so gorgeously blue-violet to surpass the average flower garden.  Giant Foxtail Grass (Setaria magna) was swaying in the breeze with the bristly inflorescence actually the size of a fox’s tail.

But the great encounters were all three “important” Agave species growing untended in Florida.  Agaves are about as fascinating as they are beautiful, with a complex history in human affairs.

Agave sisalana (by JB)

First on the list is an abundant but definitely non-native Agave.  Florida once was a hotbed of research on fiber plants, one of them being Agave sisalana, the source of commercial sisal fibers, as in ropes, doormats, and similar rough-scratchy commodities.  Agave sisalana is still with us in scrubby places.  It is the only common Agave in natural areas having no (or few, small, and irregular) prickles along the margins of mature leaves. Recognize this species from the distance by its straight narrow leaves with comparatively parallel margins.  Agave sisalana is a Florida Exotic Pest Plant Council Category II invasive exotic, which raises a question, how can a seedless species invade?

That’s easy:  Agave sisalana, like most agaves, forms “bulbils” in its maturing inflorescence. Bulbils are baby clones of the parent plant; they represent vegetative reproduction and do not grow from sprouting seeds. Neither fruits nor seeds are known in A. sisalana.  The bulbils are tougher than nails, and can float and can last forever unrooted; they are the “perfect” propagules.  Bulbils are useful for humans wanting to cultivate agaves, which has been goin’ on a long time.

Agave remains decorate human excrement on the order of 6000 years old in caves.    CLICK and

CLICK AGAIN 

(Do you think somebody will be examining our leavings 6000 years from now?)

Agave sap burns human flesh (believe me!) to the point of being dangerous to the eyes, yet pre-Europeans served agaves in the kitchen, wrapping food in the waxy cuticle, chewing quids made of the leaves, eating the plant flesh, and sipping the sap in beverages.  The last-mentioned practice grew into a Mexican industry.  Just ask Jose Cuervo.

Agave fibers are beautiful strong, easily extracted by rotting the flesh off of the leaf, and just plain nice.   We’re talking about ancient cordage, hammocks, and fishing gear.

Prehistoric sandals probably made at least in part of Agave fibers (from the second link provided above)

So now a few strands of our story come together.   Agaves originated almost certainly in or near Mexico and Texas where human civilization is ancient.  The plants were valuable for foods, drinks, and fibers.   They are easy to store, move, and plant.  This all ties into a big Agave fact.  This is important, so listen carefully:  multiple named “species” of Agaves are in fact ancient cultivars and hybrids, created and moved around by the hand of people and their canoes.  This helps explain the sterility, wacky variation patterns, mixed chromosome numbers, and distributions of some “species,” including the Florida “natives.”

Not proven, but personally I am convinced that that’s the story behind the Agaves distributed among the Caribbean Islands.   Ancient Caribbean-dwellers were expert mariners and fisher-persons.

And all this begs a huge inadequately investigated question—a question hobbled by a reluctance among traditional taxonomic botanists to take pre-Columbian civilization into account in assessing modern plant distributions.  The question is: how did agaves come to Florida?  Possibility 1:  The Tex-Mex scrub flora around the Gulf was more or less contiguous with present-day Florida scrub.  There are western carry-overs from those times still with us in Florida.  Possibility 2:  Maybe the indestructible bulbils floated across the Gulf or Caribbean Sea, or maybe seeds fluttered here on the salty breezes.  Possibility 3:  If humans were growing agaves on Caribbean Islands, couldn’t the canoes have stopped by for a Florida vacation?   Or could humans have carried bulbils around the Gulf from Mexico?

Agave decipiens (by JB)

The level of involvement of Florida in pre-Columbian Caribbean commerce is not known.  Those who wonder how Papayas got here ponder this.  Here is an unstudied silly notion:  our Florida Agave decipiens resembles the Caribbean Agave karatto.  In Flora of North America, botanists James L. Reveal and Wendy Hodgson suspected the history of Agave decipiens to be rooted in human activity:  “Agave decipiens might have been introduced from Latin America by Native Americans; it is not otherwise known from the wild. The proliferation of chromosome numbers suggests prolonged human propagation and a probable hybrid origin.”

Agave decipiens is a large Florida endemic recognized by the even and well-developed (although of variable length) bristles fully along the leaf margins.  The leaves are almost-straight, with little twists and shape irregularities; the margins not as parallel as in Agave sisalana, which differs further by having no or very few marginal prickles.  There can sometimes be a short “trunk” at the base.  The species is beautiful and in cultivation, although a glance at Google Images reveals material cultivated under this name to be a little “dubiously identified” at times.

Even prettier is our likewise endemic Agave neglecta.   The leaves are broader (> 15 cm) than those of A. decipiens and of A. sisalana, and far more curved.   The fine mini-prickles are restricted to the lower half of the leaf margin,  As with Agave sisalana, fruits are reportedly not produced.   (However, there are specimens with fruits bearing this ID in Florida herbaria—see discussion below.  Sterile and fertile plants are possible—this occurs in the similar A. karatto, and could be either most likely cytological variation, or sometimes merely a question of pollination.)  The taxonomic King of Agaves, Howard Scott Gentry, as reported in Flora of North America, felt that Agave neglecta resembles Agave weberi cultivated for its fibers.  Reveal and Hodgson in FNA suggested, “The plant [A. neglecta] may well be a cultivar of A. sisalana or A. kewensis and represent an ancient introduction from Mexico.”  (We do not see the Agave sisalana similarity except for the missing fruits.)  Most agaves are pollinated by bats, which begs another question.  Do Florida agaves achieve pollination?  If pollinated, would the fruitless Agaves make fruits and seeds?  I don’t know, probably not, but worth a try with a step-ladder, paint-brush, and a few baggies.

Agave neglecta (by JB)

 
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Posted by on September 23, 2012 in Agave

 

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Monkey-Oranges, Snakebites, Rat Poison, and Memories of the 60’s

15 Sep

Monkey-Orange

Strychnos spinosa

Loganiaceae

In recent weeks John and George have focused on the beautiful Savannas Preserve State Park and its neighborhood around Jensen Beach, partly in preparation for an upcoming workshop there, partly because  it  beats working.   During all those doings, John, Park Biologist Christopher Vandello, and George teamed up to identify an invasive exotic shrub with croquet-ball fruits.  Christopher has been restoring a lovely sugar sand scrub ridge crossed by an ancient paved road with a simultaneous view of the Intracoastal and the inland “savannas” marsh.   Unfortunately this primo piece of creation is exotically invaded with  the spawn of garden waste dumped long ago:  Sansevieria, feral ornamental bromeliads, Suriname-Cherry,  Callisia, Kalanchoe, and more.  The most striking and spreading unwelcome guest  is a thorny sprawling shrub resembling at first glance Snowberry (Chiococca) but with cannonball fruits the size and shape of grapefruits and rock hard.

Strychnos spinosa (by JB)

Many species in the world have fruits of that general sort, perfect for throwing, and they’d be fun to step back 50 feet and shoot with a .22.    They look just like the citrus Bael Fruit (Aegle), but the foliage is wrong.   They look like some lemonish citrus, but the foliage is all wrong.  They look like Calabash, but the foliage is all wrong.  We took some prickly branches and vegetable bocce balls back to park headquarters, went to work on the computer,  and they turned out to be “Monkey-Oranges”  (Strychnos spinosa).  Another name is Natal-Oranges, fitting as the site has a meadow of Natal Grass (Melinis).

If we were in Africa these would be elephant snacks. People make things out of those hard “gourd” shells. (By JB)

The foliage is distinctive with opposite leaves having long smoothly upcurved veins.  Monkey-Oranges are not even related to Sunkist, but rather are (debatably) in the Loganiaceae, more familiar to Florida native plant enthusiasts  for Spigelia and Mitreola, and (debatably) Polypremum.   This is the family of the super-uber-lethal Carolina-Jessamine (Gelsemium).

That “lethal” part fits Strychnos spinosa.  The genus Strychnos is the source of the alkaloid drug strychnine, mostly (but not entirely) from the species Strychnos nux-vomica.  How does strychnine crop up in everyday life?  Rat poison.  Or if you are roughly of my “Woodstock” age you may recall exhortations from some authorities in the 1960s, “shun the LSD!, it is laced with strychnine.”   Whether or not that was ever true, strychnine is a powerful drug in the alkaloid group along with its friends likewise ending in –ine, such as morphine, codeine, nicotine, atropine, and an alkaloid I’m enjoying now as I type (you guess).   Strychnine inhibits the shut-off mechanism for nerve-muscle signals.  A high dose is a path to boot hill.  Lower controlled doses can be therapeutic, which brings us back to Strychnos spinosa.

Aging flowers (by JB)

In its native Africa the tree serves as a traditional neurological drug, applied, among other things for snakebites.  Could this be a manifestation of the genuine beneficial potential of strychnine?

The fruits also serve as food, with the extra benefit of coming in a natural “can” (that steel shell) thwarting competing critters (although big animals munch freely), bugs, and decay.   They hold up in storage for months.  I’m not hankering to savor the flavor of strychnine-laced fruits, but cultures who have been doing it for a few millennia have the hang of it.   A little superficial Google research seems to indicate that strychnine is in the seeds and in the green fruits but that ripe ones are probably more or less okay. (Forget it!)

The natural habitats— just like the Savannas State Park scrubby dunes—are desert-ish, although proximity to water seems favorable.  The tolerance for aridity, the indestructible fruits, and easy wood production make Strychnos spinosa a candidate for cultivation in dry lands, such as Israel where the tree is in cultivation.  In this interesting link, see Figures 7 and 8 taken in Israel yet also illustrating the scene in Savannas State Park yesterday.  CLICK

 
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Posted by on September 15, 2012 in Monkey-Oranges

 

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Polygonella

12 Sep

Wireweeds, Jointweeds,  Octoberflowers

Polygonella species

Polygonaceae

Two weeks ago John and George botanized a morning away in Jonathan Dickinson State Park near Hobe Sound.  The open sand areas looked like foam on the sea thanks to Octoberflower (Polygonella polygama).  This week we had chores in and near  Savannas Preserve State Park at Jensen, where another Polygonella,  Stout Jointweed (P. robusta) made the sugar sand whiter.  It is a Florida endemic or nearly so.  These and additional Polygonellas help keep Florida beautiful with their delicate mostly-white bountiful blossoms, which are on separate male and female plants in Octoberflower, but either bisexual or mixed male and female on single plants in Stout Jointweed.  The flowers of both start out white and turn to pink or rose or deeper shades, creating  impressionistic  color drifts in dense Polygonella meadows.

Octoberflower in September (by JB)

Altogether there are 11 species of Polygonella, all of them in the eastern and southern United States, most represented in Florida.  As a group, they tend to like dry sunny sandy places,  such as open areas in scrub, sometimes sandhills, or disturbed places.

Outside of our usual haunts, Polygonella basiramea and P. myriophylla are federal listed endangered Central Florida scrub endemics.  Polygonella myriophylla maintains a clear zone around itself by emitting natural herbicide(s).  This “allelopathic” ability probably occurs in other species as well, but rare and endangered species attract research.  Our Treasure Coast-ish species have bare zones around them too. Do they poison the competition?  Or do they merely grow the hot bare sand  where others fear to tread?  Or do they take advantage of the allelopathic “moats” of naturally herbicidal third parties, such as Florida-Rosemary?  All that would be fun to study.

Take a close look at a Polygonella…hey, there’s something “wrong” with that plant.  Oh, I know, the branch points are between leaves rather than immediately above the leaf-stem junction as in the rest of the plant world  (The branches originate normally but remain fused in part to the stem giving the illusion of arising midway between leaves.)  Knowing this, now you will never have trouble recognizing a Polygonella.

This shot shows the brown ocreas (cigar bands) at the places where leaves are or were, and the branching oddly spaced between the leaf attachment points. In normal plants bracning happens at the leaf attachment points. (By JB)

Also noteworthy, just above each leaf attachment point a cigar band membrane called an ocrea surrounds the stem.  The ocrea is characteristic of the Polygonaceae Family and turns up also in the big kinfolk:  Sea-Grape and Pigeon-Plum.   In some species., including our Stout Jointweed, the ocrea has long bristles on its top edge.

Faced with the heavenly flora displays of Polygonellas, the question must bas asked, what pollinates those lacey flowers?  Multiple insect species visit, but the interesting one is the Polygonella Bee Perdita polygonellae.  It is a Polygonella specialist, a single insect species dedicated to a genus of plants.  Which came first, the Polygonella or the bee?

White on white, P. robusta this week (by JB)

Kwick Key to the Common Treasure Coast Species

(The English names are inconsistent and messy.)

1. Ocrea with no bristles…2

1. Ocrea with bristles…3

2. Plants essentially leafless when flowering…Slender Wireweed,  Polygonella gracilis

2. Plants with leaves shaped like little canoe paddles…Octoberflower, Polygonella polygama

3.  Leaf blades usually < 1.3 mm wide,  the margins not translucent…Fringed Jointweed, Polygonella ciliata

3. Leaf blades to 2.5 mm wide, the margins translucent…Stout Jointweed, Polygonela robusta

 
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Posted by on September 12, 2012 in Jointweed, Octoberflower, Wireweed

 

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Nettles, Ankle Biters, and Burning Noses

02 Sep

Urtica, Laportea, and Boehmeria in the Urticaceae

Cnidoscolus and Tragia in the Euphorbiaceae

A prominent memory from fooling around the hills of West Virginia as a kid was, “be careful about jumping down into muddy ravines.”  I can still see in my mind’s eye the standard summertime ravine bottom biological community:  Jewelweed (Impatiens capensis), nettles (species of Urtica and/or Laportea), and yellowjackets (or some sort of hornet with that general appearance).  The yellowjackets were benign, but the nettles would sting the living beejeebers out of exposed epidermis….then you rubbed jewelweed juice on the welts in some vain hope of relief.  We called it “the 15-minute itch.”

Turkey baster hair of pain. (From Wayne’s World waynesword.palomar.edu)

Throughout most of the eastern U.S. the stingers are Laportea canadensis and Urtica dioica (and other Urtica species).  Laportea has alternate leaves, Urtica sports opposite leaves.

Around Palm Beach and Martin counties, Urtica and Laportea are not common, but they are a little here to punish the unwary.  Laportea aestuans (leaves alternate) is probably native to more tropical places, maybe making its way northward aided by Global Warming.  Urtica chamaedroides (leaves opposite) is scattered around Florida.   I have showed students an Urtica, probably this species, in the PBSC plant nursery in Palm Beach Gardens, apparently having hitchhiked on nursery plants.  Given the weediness of Urtica, there would be no earth-shaking amazement in coming across additional species locally.

What is astounding about Urtica and Laportea is their vengeful hairs.  Plants with toxins are a dime a dozen.  Plants with thorns, spines, and prickles are too.  But these little nettle  stinkers smite their foes with an injection of toxin.  The tip of the hair snaps off in your flesh, and movement of the hair squeezes a bulb at the base, sending a little squirt of irritant into the wound.  The whole thing looks and works like a turkey baster. The irritating “venom” seems to contain formic acid, as in ant bites.

The plants are not all bad though. Urtica is grown as a green fertilizer.

The small wind-pollinated flowers have a spring-loaded mechanism to toss their pollen onto the breeze.  The stamen filaments are bent inward as the flower develops, and when the moment of truth arrives, they pop forth explosively flinging the pollen.  How the anthers open coordinated with the springing filaments is a mystery of nature.

Does it bite? Nasty Urtica, or nice Boehmeria? You decide. (By JB)

False-Nettle, Boehmeria cylindrica is abundant around our haunts.  It looks like Urtica but has no stinging hairs.  False-Nettle brings us now to a little ethnobotany.  Members of the Nettle Family have long strong fibers.   Examples include Hemp (Cannabis), Urtica dioica (which has served as a fiber source), and Ramie, which is Boehmeria nivea, an Asian species.   Cannabis persists to this day as a weed in U.S. areas where it was grown historically for hemp.  My Michigan-dwelling brother just told me of encountering Cannabis growing spontaneously near his rural home.  I’m pretty sure that’s no smokin’ weed, but rather left over from Hemp farms once active in the area.  Florida was once a major fiber-growing and fiber-research state, and one fiber plant still with us escaped is Ramie. It differs from False Nettle by having the leaf blades white-hairy beneath and branchy (vs. spike like) flower clusters.

Oh $#%^&!! something just stung my ankle!! (Tread Softly by JB)

Although not related to Urtica and Laportea, another locally prominent nettle, Cnidoscolus stimulosus, is sometimes called Tread Softly, Bull Nettle, or Spurge Nettle.  Usually in dry sunny sandy habitats, Tread Softly is in the Spurge Family and is related to “Cuban-Spinach” (Cnidoscolus chayamansa).  I can attest from recent experience ankle contact with its stinging hairs is an epiphany.  Also related to Tread Softly, likewise in the Spurge Family, and scattered in Florida—even if our own immediate counties have few or none—are the Noseburns, species of Tragia.   They too inject a sting, and the mechanism is extra-special.   Contact with their hairs stabs a dagger of calcium oxalate into your soft skin.   This is the same stuff that puts the dumb in Dumbcanes, but that’s not for today.

To sum it up, just watch your step.

 
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Posted by on September 2, 2012 in Nettles

 

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Cyperus polystachyos a Sedge for All Nations

29 Aug

Manyspike Flatsedge

Cyperus polystachyos

Cyperaceae

This summer John loaned me a book about brouhaha over a fancy species of Orchid from South America.   Entertaining reading about obsession, rivalry, and general silliness…and food for thought.   In a world of a quarter million flowering plants, that much attention to a single species (if you can’t eat it, medicate, or turn it into fuel) is wasted opportunity.  I’m more fascinated with the crummy weeds in my back yard than with one showy big-flowered Orchid. (But then again I dig mutts from the pound.)

Today’s spotlight is on the so-called Manyspike Flatsedge, Cyperus polystachyos, which perhaps you never heard of — because there is not much to hear.  But you have seen it, and next time you see it you’ll know it. This species is nondescript, unpretentious, and you step on it, but it’ll have the last laugh.

Everyone has seen this! (Photo by JB.)

The weird thing is this species grows everywhere.   Why some species are rare, endangered, and confined to two counties in Florida, while others are taking over the world?   Manyspike Flatsedge covers Florida and ranges southward to South America.  Is it then tropical?  Well, yes, and looking northward it goes all the way to Maine.  The plant is also in Hawaii, Africa, Asia, and Australia. Where did it originate?  Where was it distributed before ships circled the Globe?  Who knows?

Look how flat the spikes are. (By JB)

When I say grows everywhere, I don’t merely mean on a global scale.  To narrow the focus locally, there is probably one within 200 yards of where you are sitting.    The habitats are just about any:  lake shores, depression ponds, roadside ditches, hammocks, pine woods, weedy roadsides, saltmarsh, shell mounds, burned forest, prairie, sand hills, and scrub.  The sites are often moist, but not necessarily, and the soil is often organically enriched but then again can be acid, alkaline, clay, lava, or sand.

The species is as varied as it is widespread, a challenge to taxonomists who disagree on its definition.  Manyspike Flatsedge can inhabit your mowed lawn, or left alone may be two feet tall.  The inflorescence may be compact or spread out, branched or not, and yellowish or red.

How does a species get around like that?   The fruits are tiny (1 mm long) achenes (fruits that resemble seeds), as is true of the other 599 species of Cyperus.  The achenes clearly float and blow around, and more importantly probably ride in or on birds.  Oh, by the way, several other species of Cyperus are global super-weeds too.  If you are not familiar with Cyperus, think of Papyrus, which is weedy itself.

Intercontinental ballistic achene (by JB)

The surface of the achene is sculptured with bumps and depressions.  And this is common on small seeds and achenes, especially perhaps those in wet habitats.  Why the patterned surface?  The leading thought in my experience is to cling to mud on birds’ feet, like mud sticks to the sculpted pattern of your waffle-stomper  hiking boots.  Another thought you encounter is that a rough irregular surface may catch the wind.  Additional notions are possible and 100% speculation:  maybe passing through a bird’s intestine a little bit of the bird’s intestinal content, natural compost, clings and helps the  achene initiate intimacy with soil mycorrhizae or other microbes,  or remain moist, or experience a tiny boost of nutrition.  Or, much more boringly, maybe the external bumps and valleys are just natural “bubble wrap.”

That this sedge grows on salty places adjacent to the sea probably helps it roam the Seven Seas.  Maybe Isaac moved it around even more.

But how will I know it when I see it?  First off, it looks like a standard “Cyperus” Flatsedge, with leaves clustered at the base and another tuft clustered at the top of a triangular stem.  The flowering spikes are utterly flat, and numerous.  Now here is the easy part:  there are just 2 styles, as opposed to the three in most of our other locally common Cyperus species.  If the styles are two and the spikes are flat, you probably found it. (And to make certain, the spikelet is under 2 mm wide and there is no elongate pointed tip on the spikelet scales.)

What do Florida, New England, Brazil, Morocco, Israel, Thailand, Polynesia, and Australia have in common?    Cyperus polystachyos.  How did that come about?  If by the hand of humans, that is quite a bioinvasion.  If by the hand of Mother Nature, and I hope so, that’s quite a helping hand.

 
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Posted by on August 29, 2012 in Manyspike Flatsedge

 

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