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Red Cross Spider Orchid Caladenia cruciformis A Threatened Species of the Heathy Woodland Community Description The Red Cross Spider Orchid is one of the large group of ‘Spider Orchids’ in the genus Caladenia, so called because of their long narrow petals and sepals. It has a single leaf, which can be up to 8cm long and 8-10mm wide, sparsely hairy and sometimes with a reddish tinge near the base. The flower stem can be up to 25 cm tall, slender, hairy, and usually dark green to purple in colour. The flower (usually one but sometimes two) can be up to 60mm across, with petals and sepals up to 40mm long, rigidly spreading and forming a distinctive cross-shape, which gives this orchid its name. It is usually deep red to crimson, with blackish club-like tips. The dorsal sepal is erect and slightly incurved. Spider Orchid Leaf Red-Cross Spider Orchid © Norm Stimson (Enviro Images) © Norm Stimson (Enviro Images) Distribution The Red Cross Spider Orchid is restricted to a few small areas in the central west of Victoria. The largest known population occurs on private land, but there are significant populations within adjacent and nearby reserves. Red-Cross Spider Orchids Source: Flora Information System, DSE 2004 Photo: Adrian Morton Red Cross Spider Orchid (Caladenia cruciformis) Habitat The Red Cross Spider Orchid is found in heathy woodland on grey sandy loam soils. The overstorey is usually Red Stringybark and Red Box, sometimes with Grey Box, Yellow Gum or Buloke. The shrub layer is typically a mixture of Daphne Heath, Flame Heath and Common Fringemyrtle and associated herb species include Early Nancy, Creamy Candles, Scented Sundew, Showy Podolepis and a variety of other orchid species. Decline and threats It is likely that this species was once more widespread, but the historical clearance of land for agriculture, harvesting of timber for firewood, and gravel extraction has removed or modified much of its former habitat. Current threats to the Red Cross Spider Orchid include unauthorised firewood collection, grazing by native and introduced animals, weed invasion, inappropriate burning and illegal collection. Life history Similar Species This species typically emerges as a small, single leaf in late autumn. The leaf usually grows to approximately 8cm long over winter, when the bud forms. Flowering usually begins in late August, and may continue for several weeks depending on seasonal conditions, and the presence of pollinators. Once pollinated, the flower collapses and the ovary begins to swell. Species similar to the Red Cross Spider Orchid are Caladenia concolor (Crimson Spider Orchid) and Caladenia formosa (Elegant Spider Orchid) both of which are generally taller, have drooping petals and sepals, and lack the blackish clubs of the Red Cross Spider Orchid. After several weeks the seed is ripe and the capsule splits, releasing thousands of fine, black seeds. From this time until the following autumn the plant persists as a dormant underground tuber, about the size of a marble. Why are threatened species important? • Ecosystem maintenance – the complex nature of ecosystem relationships means that the removal or disturbance of one part of the ecosystem could affect the functioning of many other components – our knowledge of these relationships is incomplete, so the results of loss or disturbance are unpredictable • Plants provide us with all our food and a quarter of our medicines – the potential of many plants to supply food , medicines or other commodities remains unexplored, and what other useful compounds could exist in as yet undiscovered plants? • Biological diversity is an intrinsic part of the aesthetic qualities in many areas valued in Australia for tourism and recreation • Extinction is forever… As with other Caladenia species, not every plant will flower each year. In some years, it will produce only a leaf, and in other years may remain dormant as a tuber. Conservation Status The current known population of the Red Cross Spider Orchid is approximately 1100 plants. It is classified as ‘Endangered’ under the Victorian Flora and Fauna Guarantee Act (FFG) 1988. This species is included in the ‘Recovery Plan for Twenty-five threatened Orchid Taxa of Victoria, South Australia and New South Wales 2003-2007’. Published by the Victorian Government Department of Sustainability and Environment Melbourne, September 2005 © The State of Victoria Department of Sustainability and Environment 2005 This publication is copyright. No part may be reproduced by any process except in accordance with the provisions of the Copyright Act 1968. Authorised by the Victorian Government, 8 Nicholson Street, East Melbourne. For more information contact the DSE North West Regional Office (Bendigo) on 5430 4444. This publication may be of assistance to you but the State of Victoria and its employees do not guarantee that the publication is without flaw of any kind or is wholly appropriate for your particular purposes and therefore disclaims all liability for any error, loss or other consequence which may arise from you relying on any information in this publication. www.dse.vic.gov.au