Fig 7, A.
This euphorbiaceous genus, found mainly in tropical America, with a few other
species in the PhiUppines, Australia, Madagascar and East Africa, is represented
on the island of Hispaniola by four species, one described here. These plants are
usually monoecious, the inflorescence composed mostly of pistiUate flowers, the
female flowers being at the center of the cymules, or wanting. The filaments of the
staminate flower are united, forming a short column, and the connective of the
anthers (usually 2 or 3) forms a peltate, cap-shaped mass 2- or 3-lobed at the
margin, the anther cells situated at the margins of the lobes; the female flower has
a 2~3-celled ovary, the style is thick, column-like and very shortly 3-lobed; the
fruits are globose, 3-lobed and 3-seeded, the hard endocarp splitting into 2 valves.
While studying the available material of this genus in various herbaria, I came
across a specimen collected by Ekman in the Cordillera Central in the Dominican
Republic. Ekman and Urban had suggested that this might be an undescribed species.
From the inadequate material available I did not believe it to be too different from
O. triandra L.; but, having later coUected the plant with fruits in the same area,
I was convinced that this was indeed an undescribed species, though related to O.
triandra; this I now name O. ekmanii after its first collector.
The most widespread species of this genus in America is without anv doubt
Omphalea diandra L., although it is not common. This is a high-climbing vine with
a very long inflorescence; it is found in Cuba, Jamaica, Hispaniola, the Lesser Antilles, and tropical South America. Other Antillean species have a restricted distribution and sometimes are narrowly endemic. For example, O. trichotoma Muell.-Arg. is found in coastal thickets in Cuba and Isle of Pines in the western half of the island, and O. commutata is found in the central part of Haiti and on Gonave Island with a single locality on the eastern tip of Cuba. Omphalea hypoleuca Griseb. is restricted to the limestone mountains of western Cuba (mogotes); O. triandra L. has been collected in Jamaica and Hispaniola, where it seems to be planted for its edible nuts.
Some species of the American tropics are still represented in herbaria by scanty material, and until we have more specimens to better understand the variability of the species, it will be difficult to have a definite idea of the taxa involved.