Dispersal of the moss Campylopus pyriformis on geothermal ground near the summits of Mount Erebus and Mount Melbourne, Victoria Land, Antarctica

Mount Melbourne in northern Victoria Land, Antarctica, is a glaciated 2733 in volcanic cone. The moss Campylopus pyriformis occurs on two small areas of steam-warmed snow-free ground near its summit. This moss species also oc curs in temperate regions world-wide, but has not been recorded elsewhere i n continental Antarctica. RAPD (Random Amplified Polymorphic DNA) studies o f 26 samples of C. pyriformis from two areas of heated ground on Mount Melb ourne showed there was genetic diversity within the population. Genetic evi dence for dispersal between the two sites, together with some genetic varia tion within individual colonies, indicates a single colonisation event has probably occurred at this extremely isolated location followed by multiple mutations. A single sample of moss protonema was collected 25 years ago fro m steam-warmed ground near the summit of another volcano, Mount Erebus (379 4 m), on Ross Island sonic 300 km. south of Mount Melbourne. The moss could not be identified based on morphological and reproductive criteria, as all attempts to differentiate it to a recognisable gametophyte were unsuccessf ul. The RAPD technique has now shown it to be C. pyriformis, and closely re lated to the population on Mount Melbourne.