Palynology of subtribe Scorzonerinae (Compositae: Lactuceae) and its taxonomic significance

Abstract

Pollen samples of c. 130 species from all seven genera of subtribe Scorzonerinae have so far been examined by light, scanning electron microscopy and with transmission electron microscopy for selected examples. The pollen grains are 3- (rarely 2-, occasionally 4-) colpororate and share a distinctive exine stratification and aperture configuration. Echinate and echinolophate pollen grains occur in the subtribe. Seven pollen types, distinguished primarily by the number and position of their lacunae, are described. A cladistic analysis of the pollen characters indicates the probable relationships between the genera. The results support the status, given by some authors, of Epilasia and Pterachaenia as genera distinct from Scorzonera and Ceropogon from Tragopogon. © Taylor and Francis Group, LLC.