Oxypetalum Gyrophyllum and O. Oblanceolatum, New Species of Asclepiadoideae (apocynaceae) from Brazil, and a Key for the O. Insigne Group

Oxypetalum gyrophyllum Farinaccio & Mello-Silva and O. oblanceolatum Farinaccio & Mello-Silva, two new species of Asclepiadoideae (Apocynaceae) from Brazil, are described and illustrated. Both species may be included in the O. insigne (Decaisne) Malme group. Oxypetalum gyrophyllum is closely related to O. glabrum (Decaisne) Malme, differing mainly by bigger and more circular leaves, a smaller corpusculum, and smaller teeth, which are curved inward and included versus curved outward and free. Oxypetalum oblanceolatum is immediately distinguished from all species of this group by oblanceolate leaves, an uncommon character state in the genus. A key for the species of the Oxypetalum insigne group is provided.