Coccoloba uvifera
Polygonaceae
Sea-Grape is an historical favorite in tropical horticulture, its cultivation dating back at least into the 1600s. Makes sense after all, what single tree—besides coconuts—were mariners of yore most likely to encounter? And enjoy, given the edibility of the sea “grapes”? When stranded on a desert isle, you might as well have fresh fruit to stave off scurvy, even if the fruits are 99% pit.
The Sea-Grapes are in flower now, which is not pure happenstance, given that tropical trees with small flowers pollinated by a wide range of insects blossom in unison as the rainy season arrives coincident with the seasonal surge of bugs.
April showers bring tree flowers! The trees flower now, and the “grapes” ripen in the autumn. Around the species’ range from Florida to South America the fruits reportedly are dispersed by bats, by birds, and by sea currents.
Pollination in Sea-Grape has a kink. From a breeding standpoint, the trees are of three types: male, or female, or mixed. The male vs. female division is fairly straightforward, forcing cross-breeding. Female fruits are more “expensive” for the tree make than is male pollen. With a division of sexes, individuals can specialize on making pollen or on making grapes, and avoid getting clogged up with their own pollen. In some other species, separate males and females may occur in different ratios or may occupy different microhabitats, although there is no evidence for that in Sea-Grape.
That today’s species has individuals with mixed male and female flowers is mildly mysterious. Some botanists reasonably suspect the mixed individuals to represent incomplete separation, with the mixing offering no particular benefit. But there is another more-interesting possibility: Given that Sea-Grape is a pioneer on far-flung and harsh seashores, a lone male or female individual could never colonize a new island or dune. Perhaps the mixed bi-sexual individuals, which are self-compatible, can start the party. Then their uni-sex offspring can expand and sustain the established population.
John Bradford
George Rogers
George Rogers
Dee Staley
Treasure Coast Natives 
Billl Grow
April 15, 2022 at 5:20 pm
George, Some time ago I started noticing the word Eudicot. I looked it up and have some idea of the meaning (well, maybe). Perhaps others have also been puzzled or may be. In a future blog you might want to explore where this word came from and what it informs us of.
George Rogers
April 15, 2022 at 7:34 pm
Hi Bill, Nice to hear from you. OK…will do. That would best happen in a blog re. waterlilies or maybe (Sweetbay) Magnolias, or perhaps even the weird non-native Ranunculus I recently encountered nearby…will make a point of hitting one of those soon.
theshrubqueen
April 16, 2022 at 8:08 am
Hmm, is the sexuality similar to Papayas?
George Rogers
April 16, 2022 at 8:38 am
yes in broad strokes, but with an interesting apparent difference. Papaya is an example of the flexible pattern where the sexual expression of an individual plant responds to age/environmental factors. You can get male, female, or mixed, as well as different degrees of each, responding to outside cues. Different ratios in different times and places. Sea-Grape seems, so far as is known, to be static with the sexual pattern “set” genetically. It seems from one research study in Venezuela that the ratio of male/female/mixed in a large population is probably constant, the same anywhere. There is a ton of room for looking further into that, however. Including here in FL. The functional differences in the flowers are subtle and hard to tell at a glance, although a survey at fruiting season would reveal much of what you’d need to know.
theshrubqueen
April 16, 2022 at 3:10 pm
Thanks, George. The Papayas have fascinated me watching the different flower types (now that the plant is stressed, I have had no fruit and few flowers) I have a huge seagrape and spend hours trying to rake fruit, wish they were a little less prolific.