animals with their edible flesh. The last strategy has particular benefits: Some seeds will likely be consumed along with the flesh, and those that survive the digestive tract will be dispersed far from the parent plant in the animal’s dung, a handy packet of moisture and fertilizer that leaves it ready to germinate. The Okeechobee gourd (Cucurbita okeechobeensis) is a climbing vine that produces pale, cream-colored flowers and a baseball-sized fruit—the gourd. Botanists John Kunkel Small and Liberty Hyde Bailey described it in the early 20th century; naturalist William Bartram noted it in the 18th century along the St. John’s River. Its current scarcity—after Bartram, it wasn’t seen in that region again until 1994—is due in part to clearing of land for agriculture and to flooding, especially along Lake Okeechobee. Small indicated that the gourd was common in the pond apple forests along the southern shores of Lake Okeechobee in the very early 1900s, but by 1930 he estimated the areas hosting the plant had been reduced by 95%. Thinking like a plant Evolutionary biologists Paul Martin and Dan Janzen famously researched plants that have no living seed disperser (among other oddities like plants with overbuilt thorny defenses), publishing “Neotropical Anachronisms” in Science in 1982. They describe anachronisms as morphology or other features that appear to have evolved in response to an ecological pressure or opportunity that no longer exists. Anachronistic traits have been observed in the fruit of the Kentucky coffee tree, Osage orange, and Cucurbita foetidissima, the desert gourd, among many. Consider the avocado seed. The flesh is appealing, but the seed is bitter and reportedly somewhat toxic. No animal alive today that lives anywhere near the avocado homeland could swallow the seed whole. However, as recently as the Pleistocene Epoch, there were lots of animals that could swallow an avocado, seed and all—giant sloths, mastodons, mammoths, equids, glyptodons, camels, daeodons, toxodons—the socalled megafauna. Most all of these “ice-age” megafauna were extinct by about 12,000 years ago, not long before humans took an interest in plant cultivation. The avocado and its seed are anachronistic. fall 2016 51 RIGHT A preserved fruit from the Fairchild Herbarium; about the size of a baseball. BELOW Pleistocene megafauna and an Okeechobee gourd: Long-lost partners reunited? Photos by Kenneth Setzer/FTBG
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