Just on Christmas, NOSSA received an enquiry from Tim in the South East about an orchid he had photographed. He knew about Dipodium roseum but in 20 years he had not seen one like this one.
From the photograph that he’d sent, it was obvious that it was a Gastrodia. In South Australia there are three species ranging in size from the smaller G. vescula (Limp Potato Orchid) through to G. sesamoides (Cinnamon Bells or Common Potato Orchid) to the larger G. procera (Tall Potato Orchid). Whilst G. vescula and G. procera are limited in South Australia to the South East, G. sesamoides is also found in the Southern Lofty and Kangaroo Island regions.
Tim’s orchid was G. procera. The features that set it apart from the other two were the time of year – late December whereas both G. sesamoides and G. procera would have finished flowering (and for 2014 most orchids finished flowering earlier than usual); the spike was crowded and the plant was upright but G. sesamoides has a bent or droopy spike when in bud and G. vescula is small with very few flowers.
Though Tim considered the photographs to not be very good, he’d photographed the necessary features to help with identification. Another feature seen in his picture is the warty appearance of the plant compared with the photograph of the G. sesamoides.
Although it is has no conservation rating federally and may even be considered secure in the Eastern States, in South Australia it is rated endangered, so well done to Tim for spotting it!
It was possible to identify this orchid from the information found in South Australia’s Native Orchids, an electronic book produced and sold by the Native Orchid Society of South Australia. Identification was confirmed by one of our most knowledgeable members.