Rhizanthella slateri
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Rhizanthella slateri , illustration |
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| ( Rupp ) MAClem. & PJCribb |
Rhizanthella slateri is a plant type from the family of orchids (Orchidaceae). The species is native to eastern Australia and lives completely underground.
features
Vegetative habit
Rhizanthella slateri is a leafless and rootless plant that grows underground. It has completely given up photosynthesis and accordingly no longer forms chlorophyll ; instead she lives myco-heterotrophic .
The branched rhizome of the plants, 5 to 10 millimeters thick and 100 to 150 millimeters long, is white, fleshy and covered with overlapping stipules .
blossom
The plant blooms in October / November. Then from the rhizome to just below the surface of the earth (occasionally protruding up to 2 centimeters) a flower stalk with numerous, overlapping stipules , on which a single so-called capitulum stands at the end , an upright, conical flower head with a diameter of 15 to 20 Millimeters. The capitulum is framed by around 18 white, fleshy, 6 to 8 millimeters long and 2 to 3 millimeters wide, overlapping bracts ; these are triangular and one-nerved.
The 15 to 36 tubular individual flowers are 6 to 8 millimeters long and 3 millimeters wide, violet in color and are arranged in the flattened capitulum. The densely papilous sepals and petals are not grown, but are close to each other. The sepals are 3 to 4 millimeters long and 1.8 to 2.2 millimeters wide, the petals 2 to 2.3 millimeters long and 1.5 millimeters wide.
The rear sepal is linear to thread-shaped at the tip and curved over the columna , the lateral sepals are also thread-shaped at their tip. The labellum , sitting on a 1 millimeter long stem, is broadly heart-shaped, 2 millimeters long and 2 millimeters wide, inflected, fleshy, densely papillary and deep red on the upper side.
The columna is short and wide, its wings are reduced to narrow, papillary, ear-shaped processes. The anthers are broad and curved, the stigma is thickened like a cushion.
Distribution, habitat, botanical history, status
The species is native to the border area between New South Wales and Queensland . Less than ten locations are known; the largest site on the slopes of the Alum Mountains includes only eight individuals. The plants grow in wooded, well-drained locations at altitudes between 10 and 1000 m. In contrast to Rhizanthella gardneri , the species does not seem to be dependent on a special host plant, but is found in the company of different plants, more often with eucalyptus species.
The first specimens of the species were discovered in 1931 by Ernest Slater on Alum Mountain near Buladelah in New South Wales and first described in 1932 by Herman Montague Rucker Rupp as Crypthanthemis slateri . In 1984 it was added to the genus Rhizanthella .
At another site near Buladelah there are plans to build roads that threaten the site. However, since the total extent of the population is difficult to quantify due to the subterranean way of life of the species, an estimate of the resulting threat to the species' survival is currently not possible.
Rhizanthella slateri is currently listed on Appendix 2 of the Washington Convention on Endangered Species .
swell
- David L. Jones: A complete guide to native orchids of Australia: including the island territories. , p.373, Frenchs Forest, 2006, ISBN 1-8770-6912-4
- Gwen Harden: Flora of New South Wales , Vol. 4, 1993, p. 219, UNSW Press, Kensington, ISBN 0-8684-0188-9