''Pterostylis divaricata'', commonly known as northern striped greenhood, is a species of orchid endemic to northern New South Wales. It grows in colonies of genetically identical plants. As with similar orchids, plants in flower differ from those that are not. Those not in flower have a rosette of leaves that lie flat on the ground. Plants in flower lack a rosette at the base but have up to ten translucent white flowers with green and brown stripes. This greenhood is similar to '' P. striata'' but has larger flowers and a longer tip on the dorsal sepal. Pterostylis habit (2)

Description

''Pterostylis divaricata'' 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 and when not flowering, a rosette of five to nine dark green, broad egg-shaped leaves that lie flat on the ground. Each leaf is long and wide. Plants in flower usually have only one, long, borne on a thin, smooth flowering stem high. Three to five dark green stem leaves long and wide are arranged on the side of the flowering spike. The flowers are translucent white with green and brown stripes. 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 are fused, forming a hood or "galea" over the

column A column or pillar in architecture and structural engineering is a structural element that transmits, through compression, the weight of the structure above to other structural elements below. In other words, a column is a compression member. ...

. The dorsal sepal is long, wide and gradually tapers to a thread-like tip long. The lateral sepals are erect, held closely against the galea with thread-like tips about long that are held high above the galea. The

s are oblong to lance-shaped, long, about wide and curved with flanges about wide. The sinus between the bases of the lateral sepals bulges forward with a V-shaped notch in the centre. The labellum is white with a brown tip and curves forward slightly, just visible above the sinus. Flowering occurs from March to May.

Taxonomy and naming

This greenhood was first formally described in 2016 by David Jones and Lachlan Copeland and given the name ''Diplodium divaricatum''. The description was published in the ''Australian Orchid Review'' from a specimen collected on Mount Duval. In the same year, the same authorities changed the name to ''Pterostylis divaricata'' "to allow for the different taxonomic views held at generic level within the subtribe". 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 ...

(''divaricata'') is a Latin word meaning "spread apart", referring to the spread tips of the lateral sepals. This species has previously been known as ''Pterostylis'' sp. aff. ''alata''.

Distribution and habitat

''Pterostylis divaricata'' grows with grasses, ferns and shrubs in woodland and forest on the higher parts between the

New England Tableland New England is a vaguely defined region in the north of the state of New South Wales, Australia, about 60 km inland from the Tasman Sea. The area includes the Northern Tablelands (or New England Tablelands) and the North West Slopes regions. A ...

and

Mummel Gulf National Park Mummel Gulf is a national park located in New South Wales, Australia, approximately by road north of Sydney. It is situated approximately southeast of Walcha on the unsealed Enfield Forest Road and south of the Oxley Highway. The Mummel R ...

References

{{Taxonbar, from1=Q51885547, from2=Q51885555 divaricata Endemic orchids of Australia Orchids of New South Wales Plants described in 2016 Taxa named by David L. Jones (botanist)