3. Gonolobus Michx.
One hundred to
150 species, U.S., Mexico, Central America, South America, Caribbean Islands.
A number of
authors have treated Gonolobus as a subgroup within Matelea
(Steyermark, 1963; Drapalik, 1970; Hartman, 1986b; Gleason and Cronquist,
1991). Rosatti (1989) defended Woodson’s (1941) decision to keep the two genera
separate, based on differences in anther structure and fruit morphology, noting
that in tropical America, where most of the species grow, the overall
distinctions between the two genera are much clearer than they might seem in
the limited context of only the few temperate species.