52 THE TROPICAL Garden What of the Okeechobee gourd? Is it, too, anachronistic? Pleistocene Florida was inhabited by all manner of megafauna; indeed mastodon remains are often found in the central and northern parts of the state, with a Columbian mammoth found as far south as Cutler Hammock in Palmetto Bay. So megafauna were likely contemporaries of the Okeechobee gourd. Many plants in the Cucurbitaceae family, like pumpkins and gourds, produce biochemical compounds called cucurbitacins. These impart a bitter taste, are toxins and are thought to deter herbivores from attacking the plant. The fruit, too, may repel smaller animals that would eat its flesh, as well as chew the seeds, thus destroying them. Recently, researchers analyzed bitter taste receptor genes in mammals, finding that larger animals (like elephants) had a reduced ability to detect bitterness. A large body also means toxins are more easily diluted and excreted. So this suggests megafauna like mastodons at least could have eaten the gourd. But did they? Remarkably, the Page-Ladson site in Florida’s Aucilla River contains thick layers of well-preserved American mastodon remains and dung (about 12,500 years old), and it contains gourd seeds—though not of the Okeechobee gourd. One seed was even found within the eye socket of a mastodon skull. Tantalizingly close evidence, this at least indicates mastodons ate gourds. Interestingly, Osage orange—another fruit thought to be anachronistic—was also found in the deposit. So how do anachronistic plants survive once their primary means of seed dispersal dies away? They either face extinction, or are kept going by a secondary partner. As for the avocado, humans became the seed disperser thousands of years ago, and we still are, although the avocado we know today has been cultivated for taste, size and durability. Many cucurbits likely survived thanks to human cultivation. Gourd fragments were even discovered along with the 8,000-year-old remains of the “Windover” people near Titusville, Florida. It’s odd however that no Okeechobee gourd remains have been found in the many well-preserved ancient sites in Florida, though other gourds and their seeds have. It doesn’t mean they weren’t around, but why, if mastodons ate gourds, would they not have eaten the Okeechobee? Maybe they did, or maybe it was rare then, too. I doubt it was introduced intentionally by humans, who would have cultivated it for less-bitter, larger fruit. It just may be that since the megafauna extinctions, the Okeechobee gourd has indeed been dwindling, alone and without a major partner in seed dispersal, whatever the original seed disperser was. Natural process or not, let’s at least not hasten the gourd’s extinction with more habitat destruction. The green-striped and rare Okeechobee gourd Photo courtesy of Keith A. Bradley, University of South Carolina Herbarium. One of the Cucurbita okeechobeensis in Fairchild’s Herbarium.
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