''Pterostylis bicornis'', commonly known as the horned greenhood, 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 elsew ...

to 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 ...

. Non-flowering plants have a rosette of leaves while flowering plants have a similar rosette at the base of a flowering spike with a one or two dark green, white and brown flowers. The flowers have distinctive long, thin horn-like tips.

Description

''Pterostylis bicornis'', 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. Non-flowering plants have a rosette of between three and seven fleshy, bright green leaves, each leaf long and wide. Flowering plants have a similar rosette on side-growths and one or two dark green, white and brown flowers on a flowering stem tall with three or four stem leaves. The flowers are long and about 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 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 joined to form a hood called the "galea" over the column with the dorsal sepal having a short tip and the petals narrow, horn-like tips 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, fused to each other at their base and have a slightly 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 and narrow tips long. The labellum is about long, wide with a thickened tip, curved and protruding above the sinus. Flowering occurs in June and July.

Taxonomy and naming

''Pterostylis bicornis'' was first formally described in 1987 by David Jones and Mark Clements from a specimen collected on

Mount Maroon Mount Maroon is a mountain in South East Queensland that is part of the McPherson Range. The mountain rises to above sea level about 12 km west of Rathdowney. The original indigenous name for the mountain is Wahlmoorum which means sand go ...

. The description was published in ''

Proceedings of the Royal Society of Queensland ''Proceedings of The Royal Society of Queensland'' is a multidisciplinary scientific journal published by The Royal Society of Queensland The Royal Society of Queensland was formed in Queensland, Australia in 1884 from the Queensland Philo ...

''. 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 ...

(''bicornis'') 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 "two-horned".

Distribution and habitat

The horned greenhood grows in shallow soil pockets in rock crevices with moss and lichen. It is only known from Mount Maroon and the

Mount Barney National Park Mount Barney National Park is a national park in Queensland (Australia), 90 km southwest of Brisbane. It amalgamated the adjacent Mount Lindesay (Queensland), Mount Lindesay National Park in 1980. It is part of the Scenic Rim Important Bird ...

in southern

Queensland ) , nickname = Sunshine State , image_map = Queensland in Australia.svg , map_caption = Location of Queensland in Australia , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , established_ ...

and from near

Woodenbong Woodenbong is a rural village in the Kyogle Shire of northern New South Wales. It is situated 10 km south of the Queensland border and five kilometres south of the junction of the Summerland Way and the Mount Lindesay Road, which leads to ...

in far northern

New South Wales ) , nickname = , image_map = New South Wales in Australia.svg , map_caption = Location of New South Wales in AustraliaCoordinates: , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , es ...

Conservation

''Pterostylis bicornis'' is classified as "vulnerable" 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 ...

(EPBC Act). The main threats to the species are illegal collection, inappropriate fire regimes and weed invasion.

References

{{Taxonbar, from=Q15492794 bicornis Endemic orchids of Australia Orchids of New South Wales Orchids of Queensland Plants described in 1987