Palynology of South American Podostemaceae: I. Apinagia Tul.

Abstract

Pollen structure of three species of Apinagia (Podostemaceae) that grow in the Paranean Province, South America, are described. The pollen grains are isopolar, tricolpate, spheroidal to subprolate, with microechinate sculpture. The ornamental processes are of different size. The colpus membrane has similar ornamentation as the non-apertural wall but larger. Ultrastructural studies of the wall demonstrated that the ectexine is composed of a tectum, a granular infratectum formed by cylindrical elements, similar to rounded cords of different diameter and a basal layer. The general morphology and exine ultrastructure are similar to that of other taxa of Podostemaceae ( Marathrum , Mourera , Podostemum , Tristicha ). These are the first palynological descriptions of Apinagia , using transmission electron microscopes (TEM). Pollen quantity per anther is also reported for the first time.