Pterostylis atrans
Species of orchid
From Wikipedia, the free encyclopedia
Pterostylis atrans, commonly known as the dark-tip greenhood[2] or blunt-tongue greenhood,[3] is a species of orchid endemic to south-eastern Australia. As with similar greenhoods, plants in flower differ from those that are not flowering. The non-flowering plants have a rosette of leaves flat on the ground, but the plants in flower have a single flower with leaves on the flowering stem. In this species, the flower is green and reddish brown with a protruding sinus and small club-like tips on the ends of the lateral sepals.
| Dark-tip greenhood | |
|---|---|
| |
| Pterostylis atrans growing near Mount Toolebewong | |
Scientific classification  | |
| Kingdom: | Plantae |
| Clade: | Embryophytes |
| Clade: | Tracheophytes |
| Clade: | Spermatophytes |
| Clade: | Angiosperms |
| Clade: | Monocots |
| Order: | Asparagales |
| Family: | Orchidaceae |
| Subfamily: | Orchidoideae |
| Tribe: | Cranichideae |
| Genus: | Pterostylis |
| Species: | P. atrans |
| Binomial name | |
| Pterostylis atrans | |
| Synonyms[1] | |
Description
Pterostylis atrans is a terrestrial, perennial, deciduous, herb with an underground tuber and when not flowering, a rosette of ovate leaves, each leaf 10–35 mm long and 10–30 mm wide. Flowering plants have a single flower 14–20 mm long and 10–12 mm wide borne on a stem 150–300 mm high with between three and five spreading stem leaves. The flowers are green with a reddish-brown, down curved tip. The dorsal sepal and petals are fused, forming a hood or "galea" over the column and the dorsal sepal has a thread-like tip 6–9 mm long. The lateral sepals are held closely against the galea, have erect, thread-like tips 15–20 mm long with small club-like tips and a protruding, platform-like sinus between their bases. The labellum is 9–11 mm long, about 3 mm wide, green with a blunt brown tip that is just visible above the sinus. Flowering occurs from November to April.[2][3][4]
Taxonomy and naming
Pterostylis atrans was first formally described in 1994 by David Jones from a specimen collected in the Brindabella Range. The description was published in Muelleria.[1][4] The specific epithet is "from the Latin word atrans, darkening, in reference to the dark red-brown colouration towards the apex of the galea".[2]