''Pterostylis macrocalymma'', commonly known as the large-hooded rufous greenhood or Murchison rustyhood is a plant in the orchid family

Orchidaceae 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 ...

and 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 else ...

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 ...

. Both flowering and non-flowering plants have a relatively large rosette of leaves. Flowering plants also have up to ten or more white flowers with bold green or pale brown lines and a broad spoon-shaped, insect-like labellum.

Description

''Pterostylis macrocalymma'' 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 wid ...

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, ...

, herb with an underground tuber and a rosette of between six and ten leaves. The leaves are long and wide. Flowering plants have a rosette at the base of the flowering stem but the leaves are usually withered by flowering time. Up to ten or more translucent white flowers with bold pale green or brown lines are borne on a flowering stem tall. The flowers lean forward and are long and wide. 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 c ...

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 coine ...

and petals form a hood or "galea" over the column with the dorsal sepal having a narrow 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 co ...

sepals turn downwards and are the same width as the galea, deeply dished and suddenly taper to narrow tips long which turn forward and spread apart from each other. The labellum is fleshy, dark brown and insect-like, long, about wide with short hairs on the "head" end and five to eight long hairs on each side of the "body". Flowering occurs from August to early October.

Taxonomy and naming

''Pterostylis macrocalymma'' was first formally described in 1989 by Mark Clements and David Jones from a specimen collected near where the

North West Coastal Highway North West Coastal Highway is a generally north-south Western Australian highway which links the coastal city of Geraldton with the town of Port Hedland. The road, constructed as a sealed two-lane single carriageway, travels through remote and ...

crosses the Murchison River. The description was published in ''Australian Orchid Research''. The specific epithet (''macrocalymma'') is derived from the

Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic p ...

words ''makros'' meaning "long" and ''kalymma'' meaning "a covering", "hood" or "veil" referring to the large galea of this orchid.

Distribution and habitat

The large-hooded rufous greenhood grows in woodland and shrubland and on granite outcrops between Moora, Woodanilling and Esperance in the

Geraldton Sandplains Geraldton (Wajarri: ''Jambinu'', Wilunyu: ''Jambinbirri'') is a coastal city in the Mid West region of the Australian state of Western Australia, north of the state capital, Perth. At June 2018, Geraldton had an urban population of 37,648. ...

biogeographic region.

Conservation

''Pterostylis macrocalymma'' is classified as "

Priority One Prioritization is an action that arranges items or activities in order of importance. Priority may refer specifically to: Law * Priority or right of way on the road, see Traffic § Priority (right of way) ** Priority signs, a traffic sign th ...

" by the Western Australian Government

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 ...

, meaning that it is known from only one or a few locations which are potentially at risk.

References

{{Taxonbar, from=Q15492900 macrocalymma Endemic orchids of Australia Orchids of Western Australia Plants described in 1989