Pachypodium bicolor

Pachypodium bicolor is a species of plant in the family Apocynaceae. The species has a habit of a low growing somewhat pendulant shrub with a thickened trunk and a densely branched crown composed of numerous branches. It has been elevated from a "forma" taxonomical ranking of Pachypodium rosulatum variety rosulatum forma bicolor to a full species by Lavranos and Rapanarivo in 1997. A "forma" is a specific taxonomic ranking below subspecies and usually designates the smallest degree in taxonomical nomenclature recording the slightest difference between taxa, typically based on one chief character. It chief character that distinguishes Pachypodium bicolor from other species with yellow corolla is the presence of a white corolla tube or throat to the flower. Pachypodium bicolor is part of the Pachypodium rosulatum complex, where discussion centers on rather one is dealing with one species with many varieties, as Gordon Rowley argues, or many separate distinct species. The corolla, the co......read more on Wikipedia.