External Seed Morphology of Arenaria (Caryophyllaceae) of the Southeastern United States

Abstract

Seeds of 13 southeastern United States taxa of Arenaria were examined with the scanning electron microscope. With a few exceptions, external morphology is distinctive and valuable for separating taxa at the species level. No differences were discerned, however, between the closely related A. alabamensis and A. uniflora. Arenaria glabra is variable in the degree of tubercle development, but otherwise it is identical to A. groenlandica. Interspecific variation in external seed morphology of the taxa examined does not support generic segregation of Minuartia from Arenaria.