''Pterostylis atriola'', commonly known as the snug 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 ...

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

. As with similar orchids, the flowering plants differ from those which are not flowering. The non-flowering plants only have a rosette of leaves but the flowering plants have one or two rosettes on growths from the base and up to ten small, dark green, white and brown flowers on a relatively tall flowering spike. It is a rare species, only known from four widely separated populations.

Description

''Pterostylis atriola'' 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 ...

and when not flowering, a rosette of three to six egg-shaped leaves long and wide. Flowering plants have up to ten well-spaced flowers about long and wide borne on a flowering spike high. There are three to five stem leaves long wrapped around the flower spike. The flowers are dark green and white, brown near the tip with two to four flowers are open at any time. 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 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 and has a short 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 ...

sepals are erect, held closely against the galea with thread-like tips about 3mm long which barely project above the galea. The

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 the bases of the lateral sepals is flat and the opening in front of the flower is only about wide. The labellum is about long and is not visible from outside the intact flower. Flowering occurs from January to April.

Taxonomy and naming

''Pterostylis atriola'' was first formally described in 1998 by David Jones and the description was published in the ''Australian Orchid Research'' from a specimen collected on the plains near Snug. 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 ...

(''atriola'') is from the Latin ''atriolum'', 'small room', 'hall' or 'vestibule', and refers to the small opening in the front of the flower.

Distribution and habitat

The Snug greenhood usually grows in stony places in dry forest with scattered shrubs. It occurs in widely separated locations from areas near the coast to altitudes of .

Conservation

''Pterostylis atriola'' was previously listed as "endangered" under the Australian Government ''

Environment Protection and Biodiversity Conservation Act 1999 The ''Environment Protection and Biodiversity Conservation Act 1999'' (Cth) is an Act of the Parliament of Australia that provides a framework for protection of the Australian environment, including its biodiversity and its natural and cultu ...

''. When the species was first described, the population was estimated to be about 100 individuals, but was subsequently was raised to about 1,000 when more populations were discovered. It is listed as "rare" 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=Q15491990 atriola Endemic orchids of Australia Orchids of Tasmania Plants described in 1998