Evolutionary trends in the potalieae (loganiaceae)

Abstract

Pollen grains of the genera Anthocleista, Fagraea and Potalia, which all belong to the tribe Potalieae, have been studied. Eleven pollen types were recognized and using ten evolutionary trends, it was possible to produce a scheme for the interrelationships of these pollen types. It was concluded that the relationships fall into two series. One series starts with the Fagraea elliptica type and ends with the F. racemosa and F. fragrans types. There is an early offshoot with the F. crenulata and F. ceilanica types. The second series starts with the F. umbelliflora type and ends with the Anthocleista nobilis type. The Fagraea annulata, F. bodenii, F. berteriana, and F. gardenioides types form intermediates. There is a suggestion of a close relationship within the Loganiaceae between the Potalieae and the Gelsemieae. Primitive members of the Potalieae also show resemblance in their pollen morphology to some taxa in the Gentianaceae. There was no confirmation of a relationship with the Apocynaceae. © 1978.