''Pterostylis orbiculata'', commonly known as the coastal banded greenhood, is a plant in the orchid family Orchidaceae and is endemic to the

south-west The points of the compass are a set of horizontal, radially arrayed compass directions (or azimuths) used in navigation and cartography. A compass rose is primarily composed of four cardinal directions—north, east, south, and west—each se ...

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 reddish brown, greenish brown or green with a reddish or brownish labellum with short stiff hairs.

Description

''Pterostylis orbiculata'', 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 three and six, egg-shaped leaves, each leaf long and wide, the leaves on a stalk long. When flowering, there are between two and twenty reddish brown, greenish brown or green flowers with translucent white areas borne on a flowering stem high. The flowering stem has between six and twelve lance-shaped to egg-shaped stem leaves which are long and wide. The flowers are 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 with a smooth surface and the petals are long, about wide and almost straight. The lateral sepals turn downwards and joined for most of their length forming an almost circular structure long and wide. The labellum is oblong, long, about wide, reddish or brownish and covered with short, stiff hairs. Flowering occurs from June to early August.

Taxonomy and naming

The coastal 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 orbiculatus''. The description was published in ''Australian Orchid Review'' from a specimen collected near Mogumber. In 2018 the same authors changed the name to ''Pterostylis orbiculata'' "to allow for the different taxonomic views held at generic level within the subtribe". It had previously been known as ''Pterostylis'' sp. 'coastal'. 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 ...

(''orbiculata'') is a Latin word meaning "circular", referring to the shape formed by the fused lateral sepals.

Distribution and habitat

''Pterostylis orbiculata'' occurs in Western Australia from north of Geraldton to Bunbury with a few populations further inland. It grows in shruland, woodland and forest, sometimes around granite outcrops.

References

{{Taxonbar, from=Q52044891 orbiculata Endemic orchids of Australia Orchids of Western Australia Plants described in 2017