EVOLUTION OF THE EASTERN ASIAN AND EASTERN NORTH-AMERICAN DISJUNCT GENUS SYMPLOCARPUS (ARACEAE) - INSIGHTS FROM CHLOROPLAST DNA RESTRICTIONSITE DATA

Chloroplast DNA (cpDNA) variation was surveyed with 20 restriction end onucleases for the eastern Asian and eastern North American disjunct g enus Symplocarpus (Araceae). The cpDNA phylogeny reveals a sister grou p relationship between S. foetidus from eastern North America and S. r enifolius from eastern Asia. The cpDNA divergence between the two inte rcontinental sister species is 0.61%, which suggests an estimated dive rgence time of 6.1 million years ago during the late Miocene. The Beri ng land bridge hypothesis is compatible with the estimated time of div ergence for the migration of Symplocarpus between eastern Asia and Nor th America. Furthermore, a single origin of the exothermic spadices in Symplocarpus is suggested by the phylogeny. The cpDNA data also provi de independent support for the recognition of three species within the genus. Copyright (C) 1996 Elsevier Science Ltd