Polygonum aviculare (Polygonaceae) subspecies, new records for the Flora of Iran

Polygonum aviculare is a widely distributed annual herb. Number of segregates from this highly variable taxon
has been described as independent species or different subspecies on the basis of habit, heterophyllous and homophyllous
leaves and the length of perianth tube. Most proposed subspecies are partially sympatric and their distributions have been
affected greatly by humans. Our studies show that P. aviculare has two subspecies in Iran. These infra-specific taxa can be
differentiated by length of perianth tube and some features of outer tepals.