Two Native Antarctic Vascular Plants, Deschampsia Antarctica and Colobanthus Quitensis: A New Southernmost Locality and Other Localities in The Antarctic Peninsula Area

Abstract

The only two native antarctic vascular plants, Deschampsia antarctica Desv. and Colobanthus quitensis (Kunth.) Bartl., occur mainly in the three areas with the most extensive ice-free surfaces along the Antarctic Peninsula: South Shetlands, area between Cierva Point and Cape Garcia, and Marguerite Bay. Deschampsia antarctica has a considerably wider ecological range than C. quitensis and occurs alone in the majority (58%) of the 116 localities listed; C. quitensis occurs alone only in 3% of the localities. Twenty-four new localities (14 for D. antarctica, 2 for C. quitensis, and 8 for both species) are reported. The new southernmost locality for both species are the Terra Firma Islands (68°42′S, 67°32′W). Both plants were growing vigorously and reproduced well there in 1984 and could probably occur farther south if suitable habitats were available. Cape Calmette (68°04′S, 67°13′W) is the new southernmost locality of D. antarctica on the Antarctic Peninsula mainland. Large stands of vascular plants on flat, mesic, zonal surfaces with fine soil are very rare along the Antarctic Peninsula and occur only in the offshore South Shetland Islands and in the Arthur Harbor, Anvers Island area. The ecological optimum for both species probably occurs at Point Thomas, King George Island, South Shetland Islands, where their largest stand is located. A newly found thick moss-bank dominated by Polytrichum alpestre Hoppe is reported from Lainez Point, Pourquoi Pas Island, Marguerite Bay (67°41′S, 67°48′W).