''Pterostylis platypetala'', commonly known as the broad-petalled snail orchid, is a species of orchid endemic to the south-west of Western Australia. It has a rosette of leaves and when flowering, a single green and white flower with relatively wide

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. In ideal conditions it can form colonies of hundreds of plants and often grows under

melaleuca ''Melaleuca'' () is a genus of nearly 300 species of plants in the myrtle family, Myrtaceae, commonly known as paperbarks, honey-myrtles or tea-trees (although the last name is also applied to species of '' Leptospermum''). They range in size ...

s on the edge of winter-wet areas.

Description

''Pterostylis platypetala'' is a terrestrial, perennial, deciduous,

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 leaf rosette in diameter. Flowering plants have a single green and white flower long and wide on a flowering stem high. There are three or four stem leaves long and wide with their bases wrapped around the flowering stem. The dorsal sepal and

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. ...

and the dorsal sepal tapers to a point. The petals are wider than those of similar greenhoods and extend beyond the end of the dorsal sepal. The lateral sepals are held closely against the galea, long and have thickened, club-like tips. The labellum is small and not visible from outside the flower. Flowering occurs from May to July.

Taxonomy and naming

''Pterostylis platypetala'' was first formally described in 2015 by David Jones and

Christopher French Christopher French could refer to: *Christopher French (theologian) (fl. c. 1650–c.1713), Irish professor of divinity *Chris French (Christopher Charles French) (born 1956), British psychologist *Christopher French (judge) (1925–2003), British ...

from a specimen collected in the

Wandoo National Park Wandoo National Park is a national park in Western Australia, 80 km east of Perth Perth is the capital and largest city of the Australian state of Western Australia. It is the fourth most populous city in Australia and Oceania, wi ...

and the description was published in ''Australian Orchid Review''. 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 ...

(''platypetala'') is derived from the Ancient Greek words ''πλατύς (platús)'' meaning “flat” and ''petalon'' meaning "petal", referring to the broad edges of the petals.

Distribution and habitat

The broad-petalled snail orchid grows in salmon gum and

wandoo Wandoo is the common name for a number of Western Australian ''Eucalyptus'' species, all of which have smooth white bark. The original "wandoo" is ''Eucalyptus wandoo''. Additional species have been given this name because of a perceived likeness w ...

woodland and under melaleucas on the edge of winter-wet areas. It occurs between Kalbarri and Brookton.

Conservation

''Pterostylis platypetala'' is listed 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 en ...

References

{{Taxonbar, from=Q29674319 platypetala Endemic orchids of Australia Orchids of Western Australia Plants described in 2015