Pollen Morphology and the Relationship of the Plumbaginaceae, Polygonaceae, and Primulaceae to the Order Centrospermae: Smithsonian Contributions to Botany, Number 37

摘要

Three families, Plumbaginaceae, Polygonaceae, and Primulaceae, are considered to be related to or derived from the Order Centrospermae by various authors. These three families have anthocyanin pigments in contrast to the betalains found in all but two families in the Centrospermae. In addition, all three are known to have starch-type sieve-tube plastids in contrast to the protein type found in all centrospermous families. Examination of the pollen of 134 species by SEM, TEM, and light microscopy revealed great diversity, especially in the Polygonaceae, but not the spinulose and tubuliferous/punctuate ektexine, which characterizes the vast majority of the centrospermous taxa. Recent evidence argues against a close relationship of the Plumbaginaceae, Polygonaceae, and Primulaceae with the Centrospermae, and the absence of any pollen types common to the three families further suggests that they are not closely related to each other.