THE BIOLOGY AND TAXONOMY OF THE PORTULACA-OLERACEA L (PORTULACACEAE) COMPLEX IN NORTH-AMERICA

Portulaca oleracea L. is a polyploid, cosmopolitan weed with a broad p hysiological adaptability. It is morphologically variable, grows rapid ly, is self-compatible producing large numbers of seeds that have a lo ng survivability. The variability is expressed in a series of local po pulations that exhibit clinal variation geographically. Data obtained from the literature on the biology of the species are compared to prev ious taxonomic interpretations in order to develop a more functional t axonomic treatment of this polymorphic species.