Fakahatchee Grass (Eastern Gama Grass)

Tripsacum dactyloides

(Tripsis is Greek for friction. Due to the nonslip foliage?  Dactyloides refers to fingers, no doubt the fruiting spike fingers complete with knuckles.)

Poaceae, the Grass Family

John and I devoted our investigative skills to Red Mangroves today, and before getting back into that swamp, a little more work must go down.  So in the meantime here’s something else observed this morning, if marginal to the priority of the day.

Tripsacum dactyloides is a big gorgeous nutritious grass with history.   Florida gardeners call it “Fakahatchee Grass,” plant it abundantly, and sometimes trim it to stubble.   Residents of eastern and central North America call it Eastern Gama Grass and value the species for pasture and hay. It hosts Skipper larvae.

Tripsacum is the closest relative of corn without being corn or one of its known direct ancestors.  So a word or two on corn is something we all need.  With controversy over details, corn, Zea mays,  is the outcome of over 10,000 years of artificial selection starting with a cluster of closely related wild Zea grasses native to or near Mexico.  The complex of ancestral species is known collectively as Teosinte (tee-oh-SIN-tay).   Teosinte and Tripsacum dactyloides look strikingly similar, right down to the “ears.”   The ear of corn on ancestral Teosinte is a little finger of a few stacked kernels looking just like those on modern Tripsacum.

Here is photo evidence of the resemblance:

Fakahatchee ears

Teosinte primitive “corn” ear.  Corn 10,000 years ago. Photo by Matt Levin.

Tripsacum can cross with corn and with Teosinte.  This DNA-based evolutionary tree by biologist Elizabeth Skendzic and collaborators says it all, with today’s players all tied together:

Those Zea species are Teosinte.

Some researchers have suggested that Teosinte may have contributed genes to early corn evolution.  Either way,   the potential for its future contributions to corn are more exciting, maybe disease resistance, ecological tolerances, and untold other benefits.

If Tripsacum genes can get into corn, what about the reverse?  Concerned parties have pointed out the conceivability of GMO corn genes sneaking into wild Tripsacum.   Probably not something to lie awake dreading.

To sum it up so far, I like Fakahatchee Grass because every time I walk by one I think, “there’s an almost-ancestor to corn.”  The botanical equivalent of encountering a Neanderthal in WalMart.

How does Tripsacum differ from Zea?   Tripsacum has the male and female flowers on one spike, the females toward the bottom the males at the top.   In Zea the male and female flowers have separate spikes.  Ears of corn are the female spikes, and the corn tassels are the male spikes. In Tripsacum–Zea hybrids either condition can take place.

Fakahatchee pollen-grabbing stigmas

The “male” (pollen-producing) Tripsacum flowers dangle hundreds of jiggly anthers out into the wind where pollen shakes free for dispersal.

Witness the wiggle:  CLICK

The “female” (fruit-making) flowers poke their big reddish stigmas out like antennae to grab pollen off the wind.   They might not even need all that pollination apparatus.   The plants can form fertile clonal seeds without benefit of cross-fertilization.   That is, the seed can contain a clone of the mother plant.

If Tripsacum is an almost-corn, those kernels should have been on prehistoric menus.   They were. Tripsacum remains turn up in prehistoric caves.

There’s more to Tripsacum than corniness.   It tolerates terrible soils, yet grows big and robust.  How can jumbo happen on low nutrition?   Same way legumes, casuarinas, and wax myrtles thrive on terrible soils…nitrogen fixation.   Fakahatchee Grass reportedly has nitrogen-fixing (fertilizer-making) bacteria as root associates. That ability might be useful to share with corn.

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Dig deeper.

The literature on the history of corn would fill a silo, but readers might enjoy this

CLICK