''Pterostylis lustra'', commonly known as the small sickle greenhood, is a species of

orchid Orchids are plants that belong to the family Orchidaceae (), a diverse and widespread group of flowering plants with blooms that are often colourful and fragrant. Along with the Asteraceae, they are one of the two largest families of flowering ...

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

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 ...

. Flowering plants have three to five bright green leaves at the base of the flowering stem and a single green and white, sickle-shaped flower.

Description

''Pterostylis lustra'' is a terrestrial,

perennial A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wide ...

deciduous In the fields of horticulture and Botany, the term ''deciduous'' () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves, usually in the autumn; to the shedding of petals, aft ...

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 Tubers are a type of enlarged structure used as storage organs for nutrients in some plants. They are used for the plant's perennation (survival of the winter or dry months), to provide energy and nutrients for regrowth during the next growing ...

. Flowering plants have between three and five bright green, egg-shaped to lance-shaped leaves in a loose group at base of the flowering stem, each leaf 20–60 mm long and 8–15 mm wide. A single flower 30–50 mm long and 20–27 mm wide is borne on a spike 80–200 mm high. The flowers are green, white and sickle-shaped. The

dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage * Dorsal co ...

sepal and petals 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. ...

but the dorsal sepal is longer than the petals and tapers to a point. The

lateral Lateral is a geometric term of location which may refer to: Healthcare *Lateral (anatomy), an anatomical direction *Lateral cricoarytenoid muscle *Lateral release (surgery), a surgical procedure on the side of a kneecap Phonetics *Lateral cons ...

sepal A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 The term ''sepalum'' was coined b ...

s are erect with a gap between them and the galea, have thread-like tips 20-30mm long and there is a broad notch in the sinus between them. The labellum is dark-coloured, blunt, 15–25 mm long, about 3 mm wide and protrudes above the sinus. Flowering occurs from late October to February.

Taxonomy and naming

''Pterostylis lustra'' was first formally described in 2006 by David Jones from a specimen collected in the

Wilsons Promontory National Park The Wilsons Promontory National Park, commonly known as Wilsons Prom or The Prom, is a national park in the Gippsland region of Victoria, Australia, located approximately southeast of Melbourne. The national park is the southernmost national ...

and the description was published in ''Australian Orchid Research''. 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 ...

(''lustra'') is a

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

word meaning "illuminate" or "light up".

Distribution and habitat

The small sickle greenhood is locally common in the southern half of

Victoria Victoria most commonly refers to: * Victoria (Australia), a state of the Commonwealth of Australia * Victoria, British Columbia, provincial capital of British Columbia, Canada * Victoria (mythology), Roman goddess of Victory * Victoria, Seychelle ...

where it grows in wet, swampy areas under ''

Leptospermum lanigerum ''Leptospermum lanigerum'', commonly known as the woolly teatree, is a small tree or medium shrub from the plant family ''Myrtaceae''. Its common name derives from the conspicuously hairy capsules produced as fruit, along with the fine, silky hai ...

''. It also occurs in northern

Tasmania ) , nickname = , image_map = Tasmania in Australia.svg , map_caption = Location of Tasmania in AustraliaCoordinates: , subdivision_type = Country , subdi ...

and in the south-east of

South Australia South Australia (commonly abbreviated as SA) is a state in the southern central part of Australia. It covers some of the most arid parts of the country. With a total land area of , it is the fourth-largest of Australia's states and territories ...

Conservation

''Pterostylis lustra'' is classified as "endangered' under the Tasmanian Government ''

Threatened Species Protection Act 1995 The ''Threatened Species Protection Act 1995'' (TSP Act), is an act of the Parliament of Tasmania that provides the statute relating to conservation of flora and fauna. Its long title is An Act to provide for the protection and management of th ...

''.

References

{{Taxonbar, from=Q15492689

lustra Lustra may refer to: *Lustrum (plural "Lustra"), a period of five years. *Lustra, poetry, by Ezra Pound. *Lustra, Campania Lustra is a town and ''comune'' in the province of Salerno, in the Campania region of south-western Italy. Geography The m ...

Endemic orchids of Australia Orchids of South Australia Orchids of Victoria (Australia) Orchids of Tasmania Plants described in 2006