''Pterostylis grandiflora'', commonly known as the cobra greenhood or superb greenhood, is a species of orchid endemic to south-eastern

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

. As with similar orchids, the flowering plants differ from those which are not flowering. The non-flowering plants have a rosette of leaves but the flowering plants lack a rosette and have a single flower with leaves on the flowering spike. This greenhood has a green and white, striped flower with deep red-brown markings especially on its "galea", and a sharply pointed dorsal sepal.

Description

''Pterostylis grandiflora'' 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 four to nine egg-shaped leaves. Each leaf is 4–20 mm long and 3–10 mm wide. Flowering plants have a single flower 27–35 mm long and 17–23 mm wide borne on a spike 150–150 mm high with four to nine stem leaves wrapped around it. The flowers are white with green and deep red-brown stripes and markings. 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 curves forward with a thread-like tip 3–5 mm long. The lateral sepals are erect and held closely against the galea and there is a broad, flat, platform-like protruding sinus between their bases. The labellum is 17–20 mm long, about 3 mm wide and reddish-brown and protrudes above the sinus. Flowering occurs from May to August.

Taxonomy and naming

''Pterostylis grandiflora'' was first formally described in 1810 by Robert Brown and the description was published in the '' Prodromus Florae Novae Hollandiae et Insulae Van Diemen''. 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 ...

(''grandiflora'') is derived from the Latin words ''grandis'' meaning "large" and ''flos'', genitive ''floris'' meaning flower".Backer, C.A. (1936). ''Verklarend woordenboek der wetenschappelijke namen van de in Nederland en Nederlandsch-Indië in het wild groeiende en in tuinen en parken gekweekte varens en hoogere planten'' (Edition Nicoline van der Sijs).

Distribution and habitat

The cobra greenhood grows in moist shady places in forest on the coast and tablelands of southern Queensland, New South Wales, Victoria and Tasmania.

Conservation

''Pterostylis grandiflora'' is classified as "rare" under the Tasmanian Government '' Threatened Species Protection Act 1995''.

Use in horticulture

Although easier to grow than many other greenhoods, the superb greenhood is mainly only grown by orchid enthusiasts. It must be kept dry in the dormant stage and kept moist in 50% sunlight during the growth and flowering stage.

References

External links

{{Taxonbar, from=Q7256923 grandiflora Endemic orchids of Australia Orchids of New South Wales Orchids of Queensland Orchids of Tasmania Orchids of Victoria (Australia) Plants described in 1810