''Pterostylis allantoidea'', commonly known as the shy 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 ...

which is

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 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 ...

Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...

. It has a large rosette of leaves at the base of a flowering spike and a single white flower with green or reddish-brown stripes.

Description

''Pterostylis allantoidea'', 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 and which usually grows in colonies. It has a rosette of large, dark green leaves with wrinkled edges, each leaf long and wide. When flowering, there is usually only a single, white flower with green or reddish-brown stripes. The flowers lean forwards and are long, wide and borne on a flowering spike tall. 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 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 ...

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 longer than the petals and has a thread-like tip long. 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 ...

sepals are erect with thread-like tips long with a bulging

sinus Sinus may refer to: Anatomy * Sinus (anatomy), a sac or cavity in any organ or tissue ** Paranasal sinuses, air cavities in the cranial bones, especially those near the nose, including: *** Maxillary sinus, is the largest of the paranasal sinuses, ...

between them. The labellum is egg-shaped, long, about wide, thick, fleshy, dark brown and curved and protrudes above the sinus. Flowering occurs from August to September.

Taxonomy and naming

''Pterostylis allantoidea'' was first formally described in 1940 by

Richard Sanders Rogers Richard Sanders Rogers (2 December 1861 – 28 March 1942) was a distinguished Australian medical doctor, and world authority on Australasian orchids. He described over 80 Australian orchid species, three from New Zealand and 30 from New Guinea a ...

Transactions 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 ...

(''allantoidea'') is from the Latin ''allantoideus'', 'sausage-shaped', referring to the shape of the labellum.

Distribution and habitat

The shy greenhood grows on and near granite outcrops under shrubs between Coolgardie,

Ravensthorpe Ravensthorpe may refer to any of the following places. England *Ravensthorpe, Dewsbury in West Yorkshire **Ravensthorpe railway station, Dewsbury *Ravensthorpe, Northamptonshire *Ravensthorpe, Peterborough in Cambridgeshire *Ravensthorpe, an histor ...

and

Israelite Bay Israelite Bay is a bay and locality on the south coast of Western Australia. Situated in the Shire of Esperance local government area, it lies east of Esperance and the Cape Arid National Park, within the Nuytsland Nature Reserve and the Grea ...

in the Coolgardie and

Esperance Plains Esperance Plains, also known as Eyre Botanical District, is a biogeographic region in southern Western Australia on the south coast between the Avon Wheatbelt and Hampton bioregions, and bordered to the north by the Mallee region. It is a pl ...

biogeographic regions A biogeographic realm or ecozone is the broadest biogeographic division of Earth's land surface, based on distributional patterns of terrestrial organisms. They are subdivided into bioregions, which are further subdivided into ecoregions. De ...

of Western Australia.

Conservation status

''Pterostylis allantoidea'' is classified as "not threatened" by the

Government of Western Australia The Government of Western Australia, formally referred to as His Majesty's Government of Western Australia, is the Australian state democratic administrative authority of Western Australia. It is also commonly referred to as the WA Government o ...

Department of Parks and Wildlife The Department of Parks and Wildlife (DPaW) was the department of the Government of Western Australia responsible for managing lands described in the ''Conservation and Land Management Act 1984'' and implementing the state's conservation and e ...

References

{{Taxonbar, from=Q15492225 allantoidea Endemic orchids of Australia Orchids of Western Australia Plants described in 1940 Endemic flora of Western Australia