Evolution of endemic vascular plants of Ulleungdo and Dokdo in Korea : floristic and cytotaxonomic characteristics of vascular flora of Dokdo = 울릉도 및 독도 고유 관속식물의 계통 : 독도의 식물 구계 및 세포분류학적 특성

Abstract

A total of 48 vascular plant taxa belonging to 27 families, 46 genera, 41 species, and 7 varieties are recognized in Island Dokdo. Five species of Plantago asiatica, Schizophragma hydrangeoides, Rubus phoenicolasius, Viola kusanoana, and Ampelopsis brevipedunculata are regarded as already extinct and previously reported 21 species cannot be reconfirmed in the island. Most plants are dry and salt tolerant species and no taxon confined to this island is found. In terms of species composition, Dokdo is most closely related to Ulleungdo. Only limited number of plant taxa can inhabit by the lack of diverse environments and dry and salty conditions, however, more recently, frequent visit of people and transplantation of alien species cause to introduction of weeds to the island. The results of examining chromosomes of 16 taxa indicate that no alteration of chromosome numbers in the island has been occurred. The triploid level of Cyrtomium falcatum is the first report for the species.