Type species. M . coccinea Aubl.
In America, Moronobea is the largest genus of the Moronoboideae, and is
confined to the Guianas and the basins of the Amazon, Negro and Orinoco Rivers.
Its several species, especially M . coccinea and M . riparia, provide a copious yellow
latex, as do Symphemia and Platonia. that is employed by Indians and local
people as a caulking for river boats, an adhesive in instrument fabrication, and a
pitch for torch lighting (see Schultes, Bot. Mus. Leafl. 17: 12-24. 1955).
Engler and following him, Vesque, the last two students to consider the genus
in its entirety, gave much taxonomic weight to the number of anthers per
phalange. Botli of these authors considered the anther number to be sufficiently
constant to form the basis of key separation and indeed species delimitation.
From the considerably more material that is now available, and especially from
the examination of the flowers of many trees by me in the field, it has become
clear that the number of anthers per phalange is variable, even in flowers of the
same tree, and accordingly has little diagnostic value. The form of anthers and
their orientation is of much greater usefubiess for specific delimitation.