Category Archives: Uncategorized

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Around Jupiter in a couple sites are huge ancient Live Oaks.  Odd that some of don’t have many epiphytes (mainly tillandsias, ferns, and occasional orchids) riding  up on their branches. Others are overwhelmed.   In Riverbend Park just west of Jupiter there’s a stand of magnificent live oaks, including the “Tree of Tears,” allegedly watching over the Battle of the Loxahatchee in 1838.   Several of the big old oaks in the park are covered with the Bromeliad known as Southern Needleleaf, Tillandsia setacea.  

When I say covered, I mean blanketed, coated, festooned, dripping,  and smothered, the bromeliads jammed edge-to-edge on every surface except the trunk and main vertical stems. The tillandsias are like frosting on a cake on tiny twigs and massive branches alike, sun and shade, toward the inside of the trees, and the periphery. 

Let’s make a fake ballpark calculation.  Suppose a big old live oak has 10 major branches, and each of those has 10 secondary branches, and each of those 10 minor branches, and each of those 10 branchlets, and every one of the branches and branchlets hosts (easily) 100 tillandsias,  the imaginary tree has 1 million hitchhikers, and I’ll bet that estimate is low.  Even if our math is dubious and dirty, you get the idea.  To continue to speculate,  say each tillandsia weighs on average 2 ounces,  we then  have 62 tons  of Tillandsia setacea on one tree, and that is not counting soaking wet in a strong wind, nor the decayed leaves at the base of the tillandsias.

That’s a lot of biomass, and it isn’t just sitting there doing nothing.  Any botany textbook will tell you in simple terms that epiphytes are not parasites…they are just getting a free perch “at no cost” to the host tree.   That that may not be always accurate is largely untested.  Botanists back in the 70s David Benzing and Jeffrey Seeman  wondered if certain Florida bromeliads…Spanish-Moss and Ball-Moss, were parasites on their host trees. They checked to see if the roots penetrated or choked the oak bark, and the answer was “no,” but what they found was arguably more significant, if not surprising.   The epiphytes are parasitic in their own fashion.

Live oaks tend to live in nutrient-poor soils where they depend on recycling essential nutrients from their own dropped leaves.   But what if somebody steals those essentials before they hit the ground?    Although not much studied,  Tillandsia setacea has what you might call a “trashbasket” leaf collection system (discussed in an earlier blog) where its clustered knitting-needle  leaves trap falling debris, such as oak leaves.  The falling leaves compost in the company of an arthropod fauna, in the tree presumably nourishing the Tillandsia way up in its perch.  The Tillandsia additionally has absorbent leaves able to capture dissolved nutrients from stemwash and drip-through, before they percolate to the oak roots.  Benzing and Seeman concluded that the nutrient theft is sufficient to cause decline in the host tree.  You might say, well, eventually the Tillandsia dies, and that would return the critical elements to the soil.   True, in part,  but 62 tons of organic matter tied up in an uninvited guest shading your branches is a lot of your own flesh & blood tied up permanently useless to the tree.  And some of that escapes altogether as the Tillandsia disperses seeds onto the wind. The oak is feeding an ever-growing massive “tapeworm” on its branches.

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(Thank you to everyone who ordered a weed book!)

To dig deeper on parasitic tillandsias CLICK. Here are a couple snips from that article:

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Taxodium distichum (including  T. ascendens and T. mucronatum)

(Taxodium means, roughly, resembling Yew.  Distichum means “two rows.” That is how the leaves are, usually.)

Cupressaceae

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You may now think we’re going to skip down Bald-Cypress Knee Lane, but no, been there done that.   Today it is about Bald-Cypress underground.   Not that it is easy to know much about its hidden subterranean (or submarine) life, given  the pesky overlying water and mud pudding guarded by cottonmouths.  Yes, I met one recently researching Bald-Cypress (I was researching the tree too).  

You ever wonder why Bald-Cypress trees almost never topple, despite living with shallow roots in jello?   They form a huge woven mat under the mud.   This explains two things: 1. Even hurricanes don’t push them over.   2. It is hard or sometimes impossible to match roots to individual trees.  The way the roots work, how they transport  air at least 25 feet horizontally under mud and water, is to this day still mysterious.    Arguably the best case for air exchange is through dead but still-intact water-conducting cells repurposed and re-filled with air. UF former doctoral student Helen Fisher several years ago conducted experiments on this ventilation system for Slash Pine roots, and suggested the same for Bald-Cypress. So far nobody has taken the bait and conducted a modern study on this suggestion.  Why?  Repeat: those roots are IMPOSSIBLE to access.

Speaking of swamps, let’s start with Washington DC.   The heart of the nation’s capital floats atop  a former Bald-Cypress swamp discovered during building projects  in the 1920s,  and dating back perhaps 100,000 years, with stumps still persisting 20 feet beneath the lobbyists and legislators.   Some of those stumps are 8 feet in diameter and 1700 years old when they were buried.

Maybe those old DC Bald-Cypresses were Mastodon food.    In Florida Mastodon Dung is preserved to this day in deep cold water in the Aucilla River.  Guess what the main ingredient in the Mastodon droppings is:   masticated Bald-Cypress. 

Actually 1500 years old is a baby.  There are Bald-Cypresses alive today in the Carolinas up to 2600 years old.   That boggles the mind….the trees came into existence about the same times as the Hanging Gardens of Babylon.   Their annual rings are useful for comparing ancient growth patterns over time, for example to check on climate changes from ancient times through the Industrial Revolution to present times.   Twenty-six hundred years is old, but younger than a famous Bald-Cypress no longer standing due to a fire in 2012: The late “Senator,”  right here in Florida, was a BC around  3500 years old. Now that’s BC!

Some Bald-Cypress is put underground on purpose.  Ft. Jackson guarding the Mississippi near New Orleans is a prominent example. How in a swamp in the 1820s did  you build a stout brick fort able  to withstand Civil War bombardment and  two centuries of hurricanes?    On a solid foundation available on site.   The fort rests on, you guessed it, the indestructible wood of Bald-Cypress.   All still there, the fort and its underpinnings, although not in great shape.

Let’s wind up with linked stories of survival and utility.  As Kansas biologists Benjamin Tremmel and Craig Martin described,  a Bald-Cypress was planted in the 1870s in a ravine on the campus of Benedictine College in Atchison, Kansas.  Around 1900 the ravine was filled in. The tree had half its trunk interred abruptly under the dirt fill.  It rose anew.   In 2000, a century later,  new construction forced destruction of the still-living tree which had sprouted roots on the buried trunk like a gigantic “cutting” rooting over a century in plant propagation. This swamp dweller has no issue with sediments accumulating up its trunk!  Aztecs in Mexico applied the same ability near present-day Mexico City.   To expand flooded land in Lake Texcoco would normally have required building enclosures of  vertical logs in the water, then filling in dirt.  But the Aztecs found a better way…plant taxodiums crowded in a line like a picket fence, and they soon become indestructible rot-proof living seawalls oblivious to the fill dirt applied over their roots. There are still ancient taxodiums in the Lake Texcoco site dating back to Aztec horticulture.   You can see some, and one of the largest trees in the world,  a Mexican Bald-Cypress photographed  and discussed  by David Creech in his blog “Life on the Green Side”

As deplorable a loss to the natural world draining a Bald-Cypress swamp may be,  and I’d never advocate it for research,  when one is sacrificed  for “The March of Progress,”  wow, would I love to be first on the scene to see what goes on with those roots!

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Cenchrus polystachios (Pennisetum polystachion)

Poaceae, Grass Family

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There’s a tropical invasive grass oddly not comfortable it seems in southernmost Florida, and not in northern Florida either, but in a belt a little south of the middle, including Palm Beach County.   

The species is introduced and pesky all over the tropical world from Australia to the Loxahatchee Slough.  It owes its spread to introductions as a pasture fodder, as well as to accidental introductions, such as hitchhiking in hay.   The species came to Florida no doubt among many brought as cow chow, although the place and moment are murky, before 1950. 

Missiongrass is eye-catching, being almost as tall as you are, or taller, with big feathery golden amber seedheads looking  like an image from a beer ad.   Kinda pretty.

The species is an example of the “Africanization of American grasses.”  Long story short, African grasses compete well in the warmer parts of the New World, probably tough and resilient because they are adapted to grazing by huge hungry herbivores.   About 12 important Florida grasses are African natives, including most of the large invasive bullies.

One way for a species to compete well is diversity, but who ever heard of a single species where the chromosome numbers are 18, 36, 45, 48, 52, 53, 54, 56, and 78.  That diversity reflects some form of crazy history. be interesting to know if the Florida population all has the same number of chromosomes, and if those are the same as those in Texas.  Finding out would hint at how many times the grass may have been introduced, and would take a ton of effort.   

What is interesting about all those wacky chromosome numbers is that, without delving  into a lesson on the birds and bees, for  making sperms and eggs, chromosomes generally have to match up in pairs.  That’s screwed up in Missiongrass and for it,  making seeds is not reliable.    The species has at least two workarounds….the grass can grow from fragmented stem pieces which is boring, and more interestingly, its flowers can clone directly into baby plants without that pesky sperm, egg, and embryo sex business, although that sort of trickery is it not (yet) documented in Florida. Keep your eyes open because sometimes the clonal babies start growing conspicuously while still on the parent seed head. 

It would fun to know where the name “mission” came from.   Maybe it was introduced as cattlefeed at a remote mission. Or perhaps the name refers to the grass’s “mission” to spread all over the world.

Phlebodium aureum

(Phlebodium refers to veins, as does the medical condition Phlebitis. Aureum means golden. Polypody means “many feet,” referring to the fuzzy stems.)

Polypodiaceae

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Take a look at a Cabbage Palm in the woods or in a yard.  Chances are it hosts a Golden Polypody fern hanging out of the old dead leaf bases, or even among green ones up top. 

As plant perched up on another plant, Golden Polypody pushes the envelope on the term “epiphyte.”  Its massive snakelike stem burrows intimately among the leaf bases.   It does not pull free easily, and then there are mycorrhizae.  Mycorrhizae are fungi embedded in plant roots, one end in the root, the other engaged in decaying organic matter, sending a share to the fern root.  Where are those Golden Polypody mycorrhizae going?   There’s no evidence the fern and its fungal friends penetrate into the living tissue of the palm, or cause it any harm.   Still, if you used radioactive fertilizer on the palm, would radioactivity turn up in the fern?    Funny—come to think of it—-some fertilizer can be a teensie tiny bit radioactive.

What’s known slightly better is the ability of Phlebodium ferns to suppress competitors.  There you are, a fern growing on a palm trunk.  Wouldn‘t it be convenient to poison other ferns, mosses, vines, and competitors who would like to share the palm trunk?   If you look at a lot of palms with Golden Polypodys you might conclude that they do seem surprisingly free of competing trunk-dwellers.   Hard to certain about that, but the ability has been lab-tested.   Interestingly, the fern suppresses other plants only when the fern leaves are present.   Other ferns can stifle Golden Polypody too, it is warfare! Much more study needed.  Speaking of chemo-warfare, the fern also produces a false insect hormone, polypodoaurein, no doubt to confuddle buggies who cause the fern distress.

The truly odd thing about Golden Polypody  is that it is really two species for the price of one.  This fern is a perfect example of something that is not rare in the plant world:   it has not the normal two sets of chromosomes,  but rather four sets, two from a species called Phlebodium pseudoaureum and two from Phlebodium decumanum, both of these native to Tropical America, not Florida.    (It may be a useful reminder that you and I have two sets of chromosomes, one set from your mother and one from your father. Whem mommies and daddies make a baby the baby does NOT have four sets of chromosomes.) ((Unless it is Phlebodium aureum.))

Now then, isn’t that something—-neither of the parental fern species live in the U.S. but when the two are combined into Phlebodium aureum,  it can live all the way to Georgia.    Although not studied adequately to be sure of the full situation, and for reasons I don’t want to attempt to explain in a short blog,  the two-species-in-one Phlebodium aureum is self-fertile, giving it the ability to colonize new places, such as Florida.   Come to think of it, on a much smaller scale, self-fertility is handy for a fern living isolated on a tree trunk.

Does Phlebodium aureum live together with its two “parent” species?   Yes, in Puerto Rico Phlebodium aureum (with its four sets of chromosomes) crosses with its “parent” species, each with two sets of chromosomes, the offspring having, you guessed it, three sets of chromosomes.

Zebra Longwing

Heliconius charithonia

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What’s going on back there under the passionvine foliage?  Look closely…there are two Zebra Longwing Butterflies all a flutter, and a chrysalis.  We’ll come back to that after some fun context.

Florida may claim it as our state butterfly, but so could Caribbean Islands and nations all the way into South America. The Zebras need passionvines for their hungry caterpillars, so I’ll guess without data that the butterfly’s range is related to that of the genus Passiflora.   My wife Donna and I have several species of passionvines in our butterfly garden where experience shows the Longwings have their preferred species, such as Corkystem.   When the caterpillars get on a bender along with Gulf Fritillaries, they can make short work of passion-foliage.   I’ve never seen this written anywhere, but to my eye, these colorful butterflies darken into shadows in the shade, which they like to haunt.    Butterflies come to flowers for nectar, right?  Yes, but how many eat pollen?  Today’s friend does.

Now for the main points.

1. The chrysalis is camouflaged like a dead leaf. Cool.

2. For the most part, an inverted male fertilizes the female while she is still inside the chrysalis,  as in the photo below.

3. Sometimes two males hop on the same female  chrysalis.  A female can be inseminated by more than one male, yet the two males jostle and flutter for “dibs.”

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Ludwigia octovalvis (and Eumorpha fasciata)

(Ludwigia commemorates 18^th Century German botanist Christian Ludwig.  Octovalvis indicates the fruit opens along 8 lines.)

Onagraceae (and Sphingidae) 

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The approximately 30 species of primrosewillows (Ludwigia) in Florida could keep you busy awhile.   Most but not all have bright yellow flowers, but some have no petals at all.  They range from the large invasive exotic Peruvian primrosewillow rising way taller than a human from roadside ditches  to itsy bitsy mud creepers. 

Today’s species is large and showy, sunny yellow and often in large “decorative” stands in wet habitats.  Bees love it.

Mexican primrosewillow differs most conspicuously from the Peruvian PRW by having a long  narrow nearly round fruit as opposed to a stubby four-sided fruit.  Mexican PRW is hardly “Mexican,” as it ranges seemingly natively across most of the Southeastern United States, and has become one of the tropical world’s most widespread weeds, most odiously in rice fields.

It and other ludwigias have traditional uses in medicine, not worth listing here.  The interesting thing is that this species and its kin produce linoleic acid, a fatty acid essential in human nutrition and the subject of a considerable literature in that connection.    Who knows what potential lies there.

Ludwigias are preferred, if not exclusive, host plants for the caterpillars of the banded sphinx (hawk) moth, a pollinator of the crinum lilies (and probably also similar Hymenocallis spider lilies) with which the primrosewillow shares marshy habitats.    The caterpillars are astounding in at least two ways, their enormous size (about like your index finger) and their mixed coloration scheme.    Even nibbling together on a single plant there can be camouflage green ones, showy yellow ones, and eye-catching psychedelic siblings. Wow! How? and Why? This is a situation where research and speculation swirl into one. 

Just this summer biologists CL Francois and G Davidowitz studied a related sphinx caterpillar color mix and found the differences to be controlled by a very simple genetic system, perhaps (mainly) just one gene.   This sort of suggests that the colors of the caterpillars more or less to depend on a genetic roll of the dice…sort of like, “will my next grandchild be a boy or a girl?”  (It is a girl.)   Just like a family can have boys and girls in one house, a caterpillar family can have all those different color types on one plant (as well as boys and girls). The researchers suspect that the built-in automatic color mixes give the diverse caterpillars an advantage in a diverse world. Don’t put all your eggs in one color basket.  In any place and time some may become bird food but others may be better hidden, or more conspicuously toxic.   Interesting in this connection that some are showy and others are camouflaged.  

That all is no doubt true, but it gets more complicated.  Ecologist Linda Fink, formerly of UF, has looked into the banded sphinx moth in addition to related species and found that all the color variants appear mixed on any given host plant species, and (here is the surprise), the ratios of the different colors in the mix depend on the plant species.