91. Smallanthus Mack.
About 20
species, North America to South America.
Most authors
(Steyermark, 1963; Wells, 1965; Barkley, 1986; Gleason and Cronquist, 1991)
have included the species of Smallanthus in Polymnia, but
Robinson (1978) noted differences in morphology and anatomy of the achenes,
pubescence patterns of the florets, and chromosomal base number that appear to
justify separating the two genera.