Genoplesium Plumosum

''Genoplesium plumosum'', commonly known as the Tallong midge-orchid or plumed midge-orchid, is a species of orchid endemic to New South Wales. It is a small orchid only known from a few sites near the towns of Tallong and Wingello on the Southern Tablelands and is only relatively easy to find for about a month, when it flowers. It has been classified as "Endangered" under the EPBC Act.

Description

''Genoplesium plumosum'' is a terrestrial, perennial, deciduous, sympodial herb, usually with a few inconspicuous, fine roots and a pair of more or less spherical tubers. The tubers are partly covered by a protective fibrous sheath which extends to the soil surface. There is a single cylindrical, glabrous leaf fused to the flowering stem. The leaf is long and the part which is free from the stem is long and ends below the flowers. The leaf of flowering plants is solid but the leaves on plants without flowers are hollow.

The inflorescence is a spike tall, with between one and eight, non-resupinate flowers. The flowers are more or less pendulous, moderately crowded, , greenish with purple stripes and have a purplish-red labellum. The dorsal sepal is narrowly egg-shaped, long, about wide, dished on the lower surface with smooth edges and a pointed tip. The lateral sepals are linear to lance-shaped, long, about wide and diverge from each other. The petals are narrow egg-shaped, long, about wide with a long, pointed tip. The labellum is above the column and stiffly hinged to it, and is oblong, about long, wide with hairy edges and a pointed tip. The callus is narrow egg-shaped to lance-shaped and extends nearly to the tip of the labellum. Flowering usually occurs 4 to 6 weeks following summer or autumn rainfall. The fruit is a non-fleshy, dehiscent capsule containing hundreds of seeds.

Taxonomy and naming

The first formal description of ''Prasophyllum plumosum'' was by Herman Rupp in 1942 from a specimen found near Kurnell and the description was published in ''The Victorian Naturalist''. In 1989, David Jones and Mark Clements placed it and most other species of ''Prasophyllum'' into ''Genoplesium''. In 2002 Jones and Clements have proposed moving all but one of ''Genoplesium'' back to ''Corunastylis'' but the move has not been widely accepted.

The specific epithet (''plumosum'') is a Latin word meaning "feathered".

Distribution and habitat

Tallong midge-orchid grows among low shrubs in forest and in moss gardens over sandstone mainly between Sydney Harbour and Marulan.

Conservation

''Genoplesium plumosum'' has not been observed at the type location for more than 80 years and is now only known from a total area of and with a total population estimated in 2008 to be between 250 and 280 plants near Tallong and Wingello with a few individual plants in the Morton National Park. The main reasons for its decline have been land clearing and grazing by the introduced European Rabbit (''Oryctolagus cuniculus''). The species is now listed as "Critically Endangered" in terms of the EPBC Act.

References

External links

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{{Taxonbar, from=Q15464932

plumosum
Orchids of New South Wales
Endemic orchids of Australia
Plants described in 1942