Open Access

Wendy A. Grimm, Peter H. Weston, Anthony Manea, Michelle R. Leishman

• Many aspects of the biology of Genoplesium baueri R.Br. (Orchidaceae) an endangered terrestrial orchid endemic to New South Wales, Australia, remain unknown. In this study observations were made on (1) plant morphology; (2) the biology of the fruit and seeds; (3) the biology of the plant tuber and the spatial patterning of emergent plants ; (4) the morphology of the pollen and the identity of pollen vectors and (5) to develop a preliminary description of the lifecycle of the orchid, by carrying out annual surveys of two key Genoplesium baueri populations in northern Sydney, for a 12-year period and collecting data on fruits, tubers and pollinators opportunistically. Individual plants cannot be tracked from year to year. We observed that each emergent plant produces a tubular leaf and an inflorescence of 1-15 non-resupinate flowers. Fruit capsules contained numerous tiny seeds, which were slightly larger than seeds of a closely related species, Corunastylis filiformis. The papillose surface of mature tubers of Genoplesium baueri differed greatly from the smooth, spherical tubers of Corunastylis fimbriata and is likely to be the site of orchid mycorrhizae. The occurrence of clumps of closely-packed, variously-sized tubers, each subtending single Genoplesium baueri plants, warrants investigation as development by vegetative increase at the tuber level provides one of several possible explanations. The morphology of the pollinarium and evidence of Chloropid fly-mediated pollination was observed. Our better understanding of the natural history and biology of Genoplesium baueri will contribute to orchid systematics and help inform management decisions regarding this species to ensure its persistence into the future.