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Rottboellia cochinchinensis

Poaceae

Yesterday John and George extracted three hours of botany from a streamside hammock near Stuart so loaded with green entertainment we couldn’t quit, until the temperature hit 90.   The immediate goal was to rediscover a population of Eelgrass where John intends to shoot a video we’ll all enjoy soon. The Eelgrass destination was attained, and the fun’s in the journey. That is, unless along the journey your ankles feel like bee stings, but where are the bees? Back to that in a moment. Before the pain, here are some of the nicer waypoints climbing through the poison ivy:

Mitrewort (all photos today by John Bradford)

We have a couple local species of Mitrewort or Hornpods, Mitreola, with their names coming from their two-horned fruits resembling a bishop’s mitre.

Another soggy-foot friend is Pluchea odorata, sometimes called Sweetscent (a name applied to multiple different plants). It looks so pretty and smells so medicinal, you guessed it, species of Pluchea have more medicinal history than the AMA.

Sweetscent yesterday

Mixed in with all the usual native and non-native ferns a surprise stood out, a big multi-branched fern, Macrothelypteris torresiana, Mariana Maiden Fern, one more garden fern rampaging into Florida natural areas. Why would anyone import an alien fern!? Ferns make billions of wind-blown spores. No likelihood of those escaping-eh?  Morons.  This Asian-African fern has turned up all over Florida, part of the “silent majority” of hundreds of invasive exotic species not in the public eye. It looks like the endangered rare Florida Tree Fern, but the horticultural runaway has distinctive sparse chocolatey-colored (vs. abundant usually orange-toned) scales at the base of the stalk, white whiskers under the leaf (vs. essentially no hairs), and two (vs. more) veins at the base of the stalk if you slice cleanly across it.

Mariana Maidenfern

Invasives not in the public eye include dozens of grass species. One possibly in the public ankle is so-called itch grass. (It does not itch—it stings, for hours.) Everyone who has ever been outdoors knows how plants use flesh-piercing prickers for self-defense. Odd, isn’t it, that in 12,000 species of grasses prickly is uncommon…but John and I found an example yesterday.  If you want to identifiy Rottboellia, merely look for a pencil-shaped flower spike.   Then close your eyes and grab the base of the stem firmly. If you think you snagged a porky-pine, you have found today’s grass.

This odious agricultural nuisance grows in unattractive places, and ouch. Unloved and sad. On top of all other repugnance, it is allelopathic, meaning the grass makes natural herbicides to reinforce its social isolation. How’d such a stinker get to Florida? According to web sites, probably as a “pasture improvement” introduction in the 1920’s. A lot of weird stuff happened in the 20s.

Rottboellia

Corn, sugar cane, and rice farmers hate Rottboellia. It spreads abundantly by seed and rises 10 feet in 3 months, needing prop roots to stand so tall. The seeds mingle with crop seeds, thus invading cultivated fields, sometimes massively. And, remember the toxic allelopathy? That’s another big negative in a rice paddy, right? Maybe.

Or maybe not. When life gives you itchgrass, scratch the itch. In the vicinity of Lampang, Thailand,  rice growers deliberately let the invader take over fallow fields, even deliberately sowing it in crop rotation, then plowing it in as a green manure. The manured grass retains soil water and turns into mulch and compost. Even better, its allelopathy seems to be a no-cost natural pre-emergent herbicide more suppressive of weed seedlings than young rice plants. (After the fallow year the Rottboellia presumably can be suppressed with fire and permacultured soil. Its seeds require light to sprout.)

Aren’t “green manures” usually nitrogen-fixing legumes, such as alfalfa? Let’s join in on speculation. Fact: Grasses can be surprisingly nitrogen-fixing. Fact: One reported situation where grasses are good at nitrogen fixation is in heavy black soils, such as rice paddies and along the shore where the Rottboellia poked us yesterday. Speculation: Observers in Thailand suspect our nasty grass to be nitrogen-fixing as a bonus to its green manure potency. A great study for a thick-skinned Florida student to tackle…the soil ecology and nitrogen metabolism of this unique grass.

The perfect condition of fossils never ceases to amaze and inform.

Travel complications prevented John’s and George’s weekly Friday native plant field trip, so we’ll take a side trip today. I’ve been in Pennsylvania for a taste of “Pennsylvanian Period” fossils roughly 300 million years old, my favorites being Seed Ferns. (Long-extinct seed plants with ferny leaves.)

Seed Fern leaflet from deep in a PA ravine. 300 million years old?

But who needs Pennsylvania for fossils? Florida is paleontology paradise, although vastly more recent.

Most of our local fossils date to the Pleistocene Epoch, which ran approximately 2.6 million – 12,000 years ago spanning the spell between the first humans ever, to the first humans to visit the Sunshine State.

Although dinosaurs were extinct for over 60 million years when South Florida dried out, our state hosted equally awesome paleo-mammals, such as giant ground sloths, sabretooth cats, cypress-eating mastodons, and additional furry Flintstones giants.

Mastodon lower jaw. Any DNA left there?

Today’s seashell fossils are a little smaller.   Native plant roots mingle with them. No native plants field trip is complete without fossils underfoot. A construction site is an instant museum, I find more pretty seashells in the eroded canal bank behind my house than beach combing at Sanibel.

Off the beach this week, or dug up after 74,000 plus years??

Fossil shells can be exasperating to identify. Much like identifying yellow Asteraceae wildflowers, any fool can match a specimen to a photo in a handbook,  but open another book and discover lookalikes, lots of lookalikes. Farewell confidence! But it is great fun to look and try, not to mention a taste of evolution in everyday living. The species encountered are a mix of those still with us, others still living but not nearby, and the extinct.

No, I’m not providing identifications, no confidence in my own work (although this is an “easy” one).

The expert on these matters is FAU Professor Edward Petuch, who has authored several relevant books, perhaps the most appropriate to our haunts being, “The Geology of the Everglades and Adjacent Areas” (2007) authored with Charles Roberts.

Web resources stand by to help with the exasperation. The UF Natural History Museum has an online gallery of fossil shell photos.    Another useful site is the Neogene Atlas of Ancient Life Southeastern United States.

Good luck! No single reference “does it all.”

The Pleistocene Epoch was a time of sea level fluctuations as glaciers waxed and waned, with southern Florida a blue lagoon repeatedly, except for a ring of raised “islands,” including the “Palm Beach Archipelago.”   Most of the surface area, including where we botanize, was fishy repeatedly, finally above “for good” about 74,000 years ago.

Chione shells are the vast majority around my house.

The repeated dousings, climate wobbles, landform changes, and disturbances across space and time make for a complex system of fossil formations and paleo-communities across South Florida.  The shells in my canal bank probably date back over 74,000 years, and in other places can be far older. After all the many millennia some look like they came from a tourist trap, some even remain glossy and colorful.

Fresh and new after a few eons

Everybody…get in your niche!

Today John and George visited the wading birds in Savannas Preserve State Park.  What a photo op!  John took the Snowy Egret action photos, and I took the others under John’s photo master supervision enjoying the use of my ancient and just-repaired 1970s reflector lens adapted happily to a modern camera.

I’m pink and I dabble.

There’s something about a marsh to make you think of the big picture, maybe because you see so much at once: the open primitive diorama underscoring those big wading birds as the modern-day dinosaurs they are.   Bird diversity helped Darwin envision evolution, so today John and George were 2015 Darwins.   If Darwin hadn’t figured it all out back in the 1830s, we should have today because Darwin’s Finches having nothing on the Savannas Egrets.

A Spoonbill goes around with a shovel on its face, walking along…sometimes rapidly…dabbling and swinging its bill from side to side like an elephant’s trunk. The beak looks like one of those wooden ice cream paddles in the little paper lunchroom tubs. Spoonbills eat anything from vegan to squirmy.   When the bird senses food the spoon snaps shut, and water drains out the sides leaving a tasty treat for Mr. Pinky to eat.

Yo buddy,  you stick to your niche, I’ll stick to mine, and there won’t be no trouble.

Mixed in today’s flock were Great Egrets and Snowy Egrets.  There could be a competitive situation here.  But Mother Nature is on top of that.   She wrote the “Competitive Exclusion Principle,” decreeing that no two species occupy the same niche. The big wading birds may seem to have similar competing needs,  but competition breeds specialization, like the ecosystem of diversified shoe stores in the Treasure Coast Mall.    Today’s Egrets have détente with Spoonbills.  While Spoonbills eat with spoons, Egrets prefer harpoons.

Great Egrets are easy to photograph because they hold still until they spot a tasty fish, then snap, the sharp yellow dagger stabs like lightning.

Great Egret waiting patiently and posing for portrait.

The similar Snowy Egret, with rakish hair-do and a black beak has its own non-compete clause.   Rather than ambush large prey, it does the “stingray shuffle” or flaps around stirring up such lunchables as amphibians, insects, worms, crustaceans, or small fish. Snowy Egrets can hunt in groups and “round up” the menu as the birds dance around.  Below those black legs are yellow tootsies. According to some accounts, the birds while flying dangle those yellow rakes down into the water to frighten the fish upward for an easy catch.

This photo and next, dancing flapping Snowy Egrets with their yellow feet.

So today’s bird party was a gregarious jumble of spooners, ambushers, and a yellow-toed wolf-pack each doing its own thing. Opportunity for everyone.

To go one paragraph further, the plants seem to do the same. Marshes can be quilts where single species form acre-sized patches.   The borders between the patches are often sharp, or not.   Why do marsh species often sort into monospecific stands?

I think about that at Wakodahatchee Wetlands and Green Cay Wetlands, vast constructed marsh areas of shallow reclaimed water. These two sites with full sun, constant water, and nutrients galore nourish millions of grateful marsh plants in a conditions “as good as it gets.” They do not have 100 per cent perfect conditions, as there may be limited oxygen in the mud, maybe some toxins in the water, or odd nutrient imbalances, but let’s pretend a shallow sea of fertilized sewer water is the perfect setting for those species thriving there. Great blankets of pickerel weed, arrowhead, bulrushes, spike-rushes and others look like a giant paint by number composition.

We might think the big species patches may merely represent each spreading out (most of them have rhizomes) from random points of origin until they bump into another patch—like expanding bacterial colonies after sneezing into a petri dish.  But it’s not so simple.  In the Google Earth helicopter view of Green Cay below, the species patch pattern relates to borders, structures, canals, cypress domes, and other physical variations an observer can see, let alone physical influences too subtle to spot.   Some species compete better along the boardwalk, some near the wooded hummocks, some near open water. There’s competitive exclusion afoot.  Even aggressive rhizomatous marsh species seem to divvy up the seemingly near-uniform wetland into divergent niches.

Green Cay, the species patchwork isn’t random. It seems related to the boardwalk, waterways, and islands.