''Pterostylis atrosanguinea'', commonly known as the crowded banded greenhood, is a plant in the orchid family Orchidaceae and is endemic to the south-west of Western Australia. The plants either have a rosette of leaves in the years when not flowering or stem leaves on a flowering spike. When flowering, it has up to twenty flowers that are dark reddish to blackish brown with translucent white areas. The labellum is dark reddish black and covered with short, stiff hairs.

Description

''Pterostylis atrosanguinea'', is a terrestrial, perennial, deciduous,

herb In general use, herbs are a widely distributed and widespread group of plants, excluding vegetables and other plants consumed for macronutrients, with savory or aromatic properties that are used for flavoring and garnishing food, for medicinal ...

with an underground tuber. Non-flowering plants have a rosette of between five and eight egg-shaped leaves, each leaf long and wide on a stalk long. When flowering, there are between five and twenty dark reddish to blackish brown flowers with translucent white areas borne on a flowering stem high. The flowering stem has between eight and fifteen lance-shaped to egg-shaped stem leaves which are long, wide and have reddish tips. The flowers are crowded near the top of the flowering stem, long and wide. The dorsal sepal and

petal Petals are modified Leaf, leaves that surround the reproductive parts of flowers. They are often advertising coloration, brightly colored or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the ''c ...

s form a hood over the column. The dorsal sepal is long and the petals are long and about wide at their widest point. The lateral sepals turn downwards and are joined for most of their length forming a broad, elliptical structure long and wide. The labellum is oblong to egg-shaped, long, about wide, dark reddish black and covered with short, stiff hairs. Flowering occurs from late May to early August.

Taxonomy and naming

The crowded banded greenhood was first formally described in 2017 by David Jones and

Christopher French Christopher French could refer to: *Christopher French (theologian) (fl. c. 1650–c.1713), Irish professor of divinity *Chris French (Christopher Charles French) (born 1956), British psychologist *Christopher French (judge) (1925–2003), British ...

and given the name ''Urochilus atrosanguineus''. The description was published in ''Australian Orchid Review'' from a specimen collected near Waroona. In 2018 the same authors changed the name to ''Pterostylis atrosanguinea'' "to allow for the different taxonomic views held at generic level within the subtribe". It had previously been known as ''Pterostylis'' sp. 'crowded'. The

specific epithet In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

(''atrosanguinea'') is derived from the Latin word ''ater'' meaning 'dark' and ''sanguineus'' meaning 'red' referring to the colour of the flowers of this orchid.

Distribution and habitat

''Pterostylis atrosanguinea'' occurs between Wongan Hills and Katanning where it grows in forest and woodland.

References

{{Taxonbar, from=Q52084260 atrosanguinea Endemic orchids of Australia Orchids of Western Australia Plants described in 2017