Pollen morphology of Euphorbia subgenus Agaloma section Tithymalopsis and related species (Euphorbiaceae)

The pollen morphology of seven species of Euphorbia, subg. Agaloma sect. Tithymalopsis (Euphorbiaceae), and ten more species added by a later worker, has been examined with light and scanning electron microscopy. Three poorly differentiated exine sculpturing patterns have been observed within the 17 species. Species of sect. Tithmalopsis do not have pollen that could be distinguished from pollen of the 10 related species of subg. Agaloma. The present results do not support the monophyly of sect. Tithymalopsis proposed by morphological and isozymic data.