Myxomycetes of subantarctic Macquarie Island

Abstract

Macquarie Island is an oceanic island located 1000 km south-east of Tasmania. The island, which lies close to but north of the Antarctic Convergence, is the southernmost island in the world with a fairly complete cover of vegetation. However, the vascular flora is impoverished and consists of only 46 species. During the period of late January to late April of 1995, 412 field collections of myxomycetes, representing at least 22 species in 11 genera, were obtained during the course of an intensive survey of fungal biodiversity on Macquarie Island. Moist-chamber cultures prepared with various types of plant debris yielded only 14 collections, but this total included three additional species and two additional genera. All but four of the species we recorded from the island are new records for the South Polar Region. Most field collections were associated with Stilbocarpa polaris (Araliaceae) and Pleurophyllum hookeri (Asteraceae), the usual dominants in the herbfield communities that commonly occur on upper beach slopes and coastal terraces. Trichia verrucosa (80 collections), Diderma alpinum (78) and Craterium leucocephalum (59) were the most consistently abundant myxomycetes. Other species represented by ≥15 collections were Didymium cf. dubium, Collaria lurida, Lamproderma arcyrioides and Didymium macquariense. The latter is a species new to science that was described from material collected during the present study. All of the species of myxomycetes now known to occur on Macquarie Island are members of the Trichiales, Physarales, Stemonitales or Echinosteliales; no member of the Liceales or Ceratiomyxales was ever collected.