''Pterostylis pusilla'', commonly known as the tiny rustyhood is a plant in the orchid family Orchidaceae and is endemic to southern

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 ...

. It has a rosette of leaves and up to nine relatively small green and reddish-brown flowers with translucent white "windows" and a dark brown, insect-like labellum.

Description

''Pterostylis pusilla'' 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. It has a rosette of between three and eight leaves, each leaf long and wide. Flowering plants have a rosette at the base of the flowering stem and up to nine green and reddish-brown flowers with translucent white panels and which are long and about wide on a flowering stem tall. There are between two and four stem leaves with their bases wrapped around the flowering stem. 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 to form a hood called the "galea" over the column, with the dorsal sepal having a narrow, upturned point long. The lateral sepals turn downwards, much narrower than the galea and have thread-like tips long. The labellum is relatively thick, reddish-brown and insect-like, about long and wide. The "head" end has many short hairs and there are between two and four longer hairs on each side of the body. Flowering occurs from September to October.

Taxonomy and naming

''Pterostylis pusilla'' was first formally described in 1918 by

Richard Rogers Richard George Rogers, Baron Rogers of Riverside (23 July 1933 – 18 December 2021) was a British architect noted for his modernist and Functionalism (architecture), functionalist designs in high-tech architecture. He was a senior partner a ...

from specimens sent to him from South Australia and Victoria. The description was published in ''

Transactions and Proceedings of the Royal Society of South Australia The Royal Society of South Australia (RSSA) is a learned society whose interest is in science, particularly, but not only, of South Australia. The major aim of the society is the promotion and diffusion of scientific knowledge, particularly in rel ...

''. 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 ...

(''pusilla'') is a Latin word meaning "very little", "small", "petty", "puny" or "insignificant".

Distribution and habitat

The tiny rustyhood usually grows in leaf litter in open forest or mallee scrub in stony soil. It is found in New South Wales south from Temora, across Victoria and in the south of South Australia in areas with an average annual rainfall of .

References

{{Taxonbar, from=Q15491567 pusilla Endemic orchids of Australia Orchids of New South Wales Orchids of South Australia Orchids of Victoria (Australia) Plants described in 1918