Friday John and George wandered through the several habitats at the Haney Creek Trail in Jensen Beach Florida, where scrub forms a patchwork among depression ponds, streams, pine woods, and weed areas—a rich place to count species, and a pretty place to enjoy Liatris, Polygonella, Goldenrod and much more in colorful autumn bloom.
All the floral beauty distracts the eye from the more subtle fruiting beauty. Turning the attention to the fruits and seeds raises the question of who eats what in the scrub. What are the ecological relationships in the scrubby food chain? (Many critters visiting the scrub are not restricted to that habitat. But bear with me.) Pygmy Mole Crickets eat algae growing in the sand. Probably most of the smaller reptiles live on scrubby arthropods. The blueberries look like birdfood to my casual eye. No doubt the Gopher Tortoise goes for Gopher Apples. Among the more conspicuous and intermittently abundant fruits are the acorns. I just read that a single Scrub Jay can store several thousand acorns per year. The cute Gopher Mouse (Florida Scrub Mouse) is an acorn eater too. CLICK
But what do they substitute when the acorns are few?
And that is all the lead-in to a puzzling question. Who eats the big, glossy, showy “seeds” (achenes) on Sandyfield Beaksedge? This is one of the world’s most under-studied plants. When you hear discussion of scrub plants you hear all day long of the various oaks, scrub-rosemary, sand-pine, lyonia species, innocence, and others, but whoever mentions Sandyfield Beaksedge? A large, tough bright green sedge scitter-scattered abundantly on that sun-baked sugar sand. Aren’t sedges supposed to prefer wet places? (Not all of them.) Sandyfield Beaksdge represents the large, fascinating, locally diverse genus Rhynchospora, whose name translates loosely as “beak seed.” (When you have rhynoplasty you have a “beak job.”) The beak is on the seedlike fruit. The beak size and shape varies among the local Rhynchospora species, from almost scary to barely visible. The genus is in every Florida habitat from standing water to the dryiest scrub. Sandyfield Beaksedge occurs throughout Florida and into other southeastern states.
In Sandyfield Beaksedge the beak looks like the cap on an acorn, making the entire little “mini-nut” resemble a shrunken acorn, enormous and ostentatious by Rhynchospora standards. Maybe the achenes are oversized due to a simple need to provide the seedling with extra protection and nutrients in the stressful habitat, but they are too colorful and eye-catching, and prominently displayed for merely that.
Thus every time I see a cluster of the large, showy, glossy little “acornlets” on the Sandyfield Beaksedge it bugs me wondering who relies on them for food. I’m ready to go sit in the scrub all night long with night-vision goggles and watch. Like little nuts, the SFBS achenes are hard and dry, not squishy and sweet. I wonder if the true scrub acorn-eaters—the Florida Jay, the Gopher Mouse, and other furry little rodents use the mystery fruits as substitute acorns as a between-meal snack. Interestingly, the fruits start out elevated on a wand, and as time passes the wand bends down to ground level, placing the fruits within easy reach of Mickey and Minnie.