''Pterostylis basaltica'', commonly known as the basalt rustyhood or basalt 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 Victoria. It has a rosette of leaves and eight to fifteen translucent white flowers with green and brown markings and a brownish, insect-like labellum. It is a rare species only known from a small area and is endangered. Pterostylis basaltica (labelled)

Description

''Pterostylis basaltica'', 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. It has a rosette of between eight and fifteen leaves at the base of the flowering spike, each leaf long and wide. The leaves are egg-shaped and pointed and have usually withered by the time the flowers open. Up to fifteen translucent white flowers with green and brown markings, long and wide are borne on a flowering spike tall. Three to five stem leaves are wrapped around the flowering spike. The dorsal

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 with the dorsal sepal having an upturned point long. The lateral sepals turn downwards, are more or less parallel, joined at their bases and with a few short white hairs. The lateral sepals have thread-like tips long and spreading apart from each other. The labellum is thick, brownish, fleshy, insect-like, about long and wide. There are six to eight pairs of spreading white hairs on the sides of the labellum and four shorter hairs on the swollen "head" end. Flowering occurs from November to December.

Taxonomy and naming

''Pterostylis basaltica'' was first formally described in 1993 by David Jones and Mark Clements from a specimen collected near

Woorndoo Woorndoo () is a town in the Western District of Victoria, Australia. The town is in the Shire of Moyne local government area, west of the state capital, Melbourne. At the , Woorndoo and the surrounding area had a population of 169. The popul ...

and the description was published in '' Muelleria''. 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 ...

(''basaltica'') refers to the basaltic soils in which this species usually grows.

Distribution and habitat

The basalt rustyhood is only known from a single small area near

Derrinallum Derrinallum is a town in Victoria, Australia, located on the Hamilton Highway, in the Corangamite Shire. The town is the centre for the surrounding farming community and lies at the foot of Mount Elephant. Mount Elephant is a 380 m-high conical b ...

with two populations on western basalt plains grassland in south-western Victoria.

Conservation

One population of ''P. basaltica'' occurs on a roadside reserve and has about 1,000 plants and the other, on private property, about 20 plants. None are in a conservation reserve. The main threats to the species are weed invasion, habitat disturbance, altered fire regimes and grazing. The species is classified as "Threatened" by the Victorian Government and as "Endangered" (EN) under the Australian Government Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act) and a recovery plan has been prepared.

References

{{Taxonbar, from=Q15492472 basaltica Endemic orchids of Australia Orchids of Victoria (state) Plants described in 1993