Synopsis of United States Bonamia, Including Breweria and Stylisma (Convolvulaceae)

Peter’s treatment of the Convolvulaceae (in Engler & Prantl, 1897) accepts Bonamia as a monotypic genus of Madagascar, but with the remark that it is hardly distinct from the chiefly African and Australian genus Breweria. Hallier (1893 and 1897) considered the two to belong to a single, largely Old World genus, and in this he has been followed by van Ooststroom (1953). An American student can hardly do better than accept the judgment of these two specialists, based as it is on detailed and exhaustive studies. This has recently been done by O’Donell (1959), and I follow suit. There remains the small group of species of the Southeastern United States treated by Peter as Breweria subg. Stylisma, but accepted by Hallier as constituting a distinct genus. Fernald and Schubert (1949) followed Peter, without comment. House (1907) and Small (in both his Flora and the later Manual) followed Hallier, but with errors. No new evaluation of Stylisma has been made since Hallier’s publication of 1897. Below are summarized the distinguishing features of Bonamia (including Breweria) and Stylisma as given by previous authors, with the addition of a stigma character not previously stressed.