Pterostylis jacksonii

Southwest granite snail orchid
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Monocots
Order:	Asparagales
Family:	Orchidaceae
Genus:	Pterostylis
Species:	P. jacksonii
Binomial name
	Pterostylis jacksonii; D.L.Jones & C.J.French [1]

Last updated May 03, 2019

Pterostylis jacksonii, commonly known as the southwest granite snail orchid, is a species of orchid endemic to the south-west of Western Australia. Both flowering and non-flowering plants have a rosette of leaves flat on the ground and flowering plants have a single green and white flower. It is only known from between Walpole and Albany.

Endemism is the ecological state of a species being unique to a defined geographic location, such as an island, nation, country or other defined zone, or habitat type; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. The extreme opposite of endemism is cosmopolitan distribution. An alternative term for a species that is endemic is precinctive, which applies to species that are restricted to a defined geographical area.

Western Australia is a state occupying the entire western third of Australia. It is bounded by the Indian Ocean to the north and west, and the Southern Ocean to the south, the Northern Territory to the north-east, and South Australia to the south-east. Western Australia is Australia's largest state, with a total land area of 2,529,875 square kilometres, and the second-largest country subdivision in the world, surpassed only by Russia's Sakha Republic. The state has about 2.6 million inhabitants – around 11 percent of the national total – of whom the vast majority live in the south-west corner, 79 per cent of the population living in the Perth area, leaving the remainder of the state sparsely populated.

In botany, a rosette is a circular arrangement of leaves or of structures resembling leaves.

Description

Pterostylis jacksonii is a terrestrial, perennial, deciduous, herb with an underground tuber and a compact rosette of leaves 15–35 mm (0.6–1 in) in diameter. Flowering plants have a single green and white flower 9–11 mm (0.35–0.43 in) long and 5–8 mm (0.2–0.3 in) wide on a flowering stem 40–80 mm (2–3 in) high, sometimes with a light brown tinge. There is a single stem leaf 6–8 mm (0.2–0.3 in) long and 3–4 mm (0.1–0.2 in) wide on the flowering stem. The dorsal sepal and petals are fused, forming a slightly inflated hood or "galea" over the column. The lateral sepals are held close to the galea, almost closing the front of the flower and have erect, thread-like tips 14–17 mm (0.6–0.7 in) long. The labellum is broad but not visible from outside the flower. Flowering occurs in June and July.^[2]

A perennial plant or simply perennial is a plant that lives more than two years. Some sources cite perennial plants being plants that live more than three years. The term is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also widely used to distinguish plants with little or no woody growth from trees and shrubs, which are also technically perennials.

In the fields of horticulture and botany, the term deciduous (/dɪˈsɪdʒuəs/) 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, after flowering; and to the shedding of ripe fruit.

Herbaceous plants in Botany, frequently shortened to herbs, are vascular plants that have no persistent woody stem above ground. Herb has other meanings in cooking, medicine, and other fields. Herbaceous plants are those plants that do not have woody stems, they include many perennials, and nearly all annuals and biennials, they include both forbs and graminoids.

Taxonomy and naming

Pterostylis jacksonii was first formally described in 2014 by David Jones and Christopher French from a specimen collected in the Mount Frankland National Park and the description was published in Australian Orchid Review. The species had previously been known as Pterostylis sp. 'granite'.^[3] The specific epithet (jacksonii) honours William Pownall Jackson, who discovered this species.^[3]

David Lloyd Jones is an Australian horticultural botanist and the author of a large number of books and papers, especially on Australian orchids.

Mount Frankland National Park is a national park in the South West region of Western Australia, 327 km (203 mi) south of Perth. The park is part of the larger Walpole Wilderness Area that was established in 2004, an international biodiversity hotspot.

Botanical nomenclature is the formal, scientific naming of plants. It is related to, but distinct from taxonomy. Plant taxonomy is concerned with grouping and classifying plants; botanical nomenclature then provides names for the results of this process. The starting point for modern botanical nomenclature is Linnaeus' Species Plantarum of 1753. Botanical nomenclature is governed by the International Code of Nomenclature for algae, fungi, and plants (ICN), which replaces the International Code of Botanical Nomenclature (ICBN). Fossil plants are also covered by the code of nomenclature.

Distribution and habitat

The southwest granite snail orchid grows with moss on granite outcrops between Walpole and Albany in the Warren biogeographic region.^[2]^[4]

Warren, also known as Karri Forest Region and the Jarrah-Karri forest and shrublands ecoregion, is a biogeographic region in southern Western Australia. Located in the southwest corner of Western Australia between Cape Naturaliste and Albany, it is bordered to the north and east by the Jarrah Forest region. Its defining characteristic is an extensive tall forest of Eucalyptus diversicolor (karri). This occurs on dissected, hilly ground, with a moderately wet climate. Karri is a valuable timber and much of the karri forest has been logged over, but less than a third has been cleared for agriculture. Recognised as a region under the Interim Biogeographic Regionalisation for Australia (IBRA), and as a terrestrial ecoregion by the World Wide Fund for Nature, it was first defined by Ludwig Diels in 1906.

Conservation

Pterostylis echinulata is classified as "not threatened" by the Western Australian Government Department of Parks and Wildlife.^[4]

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 environment legislation and regulations. The minister responsible for the department was the Minister for the Environment.

Related Research Articles

Pterostylis barbata, commonly known as the western bearded greenhood or bird orchid is a species of orchid endemic to the south-west of Western Australia. Flowering plants have a rosette of leaves at the base of the plant and a single translucent white flower with dark green veins on a flowering stem with up to 20 stem leaves. It is one of a number of bearded orchids, some of which have yet to be formally described, all of which have a distinctive feather-like labellum.

Pterostylis hamiltonii, commonly known as the red-veined shell orchid, is a species of orchid endemic to the south-west of Western Australia. As with similar orchids, the flowering plants differ from those which are not flowering. The non-flowering plants have a rosette of leaves but the flowering plants lack a rosette and have a single flower with leaves on the flowering spike. This greenhood has a green and white, striped flower with reddish-brown markings and forms colonies, sometimes of thousands of plants.

Pterostylis angusta, commonly known as the narrow shell orchid, is a species of orchid endemic to the south-west of Western Australia. As with similar greenhoods, the flowering plants differ from those which are not flowering. The non-flowering plants have a rosette of leaves flat on the ground but the flowering plants have a single flower with leaves on the flowering spike. In this species the flower is green, white and brown with an inflated base, a narrow hood and the longest labellum of any Western Australian Pterostylis species.

Pterostylis aspera, commonly known as the rough shell orchid, is a species of orchid endemic to the south-west of Western Australia. As with similar greenhoods, the flowering plants differ from those which are not flowering. The non-flowering plants have a rosette of leaves flat on the ground but the flowering plants have a single flower with leaves on the flowering spike. In this common species, the flower is white with green and reddish-brown stripes and a short, straight labellum.

Pterostylis dilatata, commonly known as the robust snail orchid, is a species of orchid which is endemic to the south-west of Western Australia. Non-flowering plants have a rosette of leaves but flowering plants lack a rosette and have a single green and white flower on a flowering stem with stem leaves. The flowers appear in winter and have lateral sepals which almost close off the front of the flower.

Pterostylis macrocalymma, commonly known as the large-hooded rufous greenhood or Murchison rustyhood is a plant in the orchid family Orchidaceae and is endemic to the south-west of Western Australia. 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.

Pterostylis microphylla, commonly known as the small rosette snail orchid, is a species of orchid endemic to the south-west of Western Australia. As with similar greenhoods, the flowering plants differ from those which are not flowering. The non-flowering plants have a rosette of leaves flat on the ground but the flowering plants have a single flower with leaves on the flowering spike. In this species, the flower is white and green with narrow, erect lateral sepals and a small labellum.

Pterostylis parva, commonly known as the fawn snail orchid, is a species of orchid endemic to the south-west of Western Australia. As with similar greenhoods, the flowering plants differ from those which are not flowering. The non-flowering plants have a small rosette of leaves flat on the ground but the flowering plants have a single flower with leaves on the flowering spike. In this species, the flower is small, fawn, green and white and is similar to P. timothyi but smaller in stature.

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 petals. In ideal conditions it can form colonies of hundreds of plants and often grows under melaleucas on the edge of winter-wet areas.

Pterostylis scitula, commonly known as the elegant snail orchid, is a species of orchid endemic to the south-west of Western Australia. Both flowering and non-flowering plants have a small rosette of leaves flat on the ground. Flowering plants have a single, small green and white flower with leaves on the flowering stem.

Pterostylis brevichila, commonly known as the dwarf shell orchid, is a species of orchid endemic to the south-west of Western Australia. As with similar greenhoods, the flowering plants differ from those which are not flowering. The non-flowering plants have a rosette of leaves flat on the ground but the flowering plants have a single flower with leaves on the flowering spike. In this species, the flower is small and white with brown stripes and is similar to P. aspera but smaller in stature.

Pterostylis brunneola, commonly known as the giant snail orchid, is a species of orchid endemic to the south-west of Western Australia. Both flowering and non-flowering plants have a large rosette of leaves flat on the ground and flowering plants have a single distinctive white flower with pale fawn stripes and have leaves on the flowering spike. This species often forms large colonies, sometimes with Caladenia species.

Pterostylis echinulata, commonly known as the hairy-leafed snail orchid, is a species of orchid endemic to the south-west of Western Australia. Both flowering and non-flowering plants have a compact rosette of leaves flat on the ground and flowering plants have a single pale yellowish-green flower.

Pterostylis elegantissima, commonly known as the elegant rufous greenhood, is a species of orchid endemic to the south-west of Western Australia. Both flowering and non-flowering plants have a large rosette of leaves flat on the ground and flowering plants have up to eight green, white and black or brown flowers.

Pterostylis erubescens, commonly known as the red sepaled snail orchid, is a species of orchid endemic to the south-west of Western Australia. Non-flowering plants have a rosette of leaves flat on the ground but flowering plants lack a rosette and have a single large green flower which turns reddish-brown as it ages, and has leaves on the flowering spike.

Pterostylis exserta, commonly known as the exserted rufous greenhood, is a species of orchid endemic to the south-west of Western Australia. Both flowering and non-flowering plants have a large rosette of leaves flat on the ground and flowering plants have up to seven pale, transparent green and white flowers with brownish lines.

Pterostylis glebosa, commonly known as the clubbed snail orchid, is a species of orchid endemic to the south-west of Western Australia. Non-flowering plants have a rosette of leaves flat on the ground but flowering plants usually lack a rosette and have a single green and white flower with club-like lateral sepals. It sometimes forms colonies of thousands of plants.

Pterostylis karri, commonly known as the karri snail orchid, is a species of orchid endemic to the south-west of Western Australia. Both flowering and non-flowering plants usually have a small rosette of leaves and flowering plants have a single green and white flower with unusually long, erect lateral sepals. Like some similar greenhoods, it often forms dense colonies.

Pterostylis lortensis, commonly known as the Lort River snail orchid, is a species of orchid endemic to the south-west of Western Australia. Non-flowering plants have a rosette of leaves flat on the ground but flowering plants usually lack a rosette and have a flowering stem with leaves and a single pale green and white flower with narrow, club-like lateral sepals.

Pterostylis microglossa, commonly known as the Kalbarri shell orchid, is a species of orchid endemic to the south-west of Western Australia. Non-flowering plants have a rosette of leaves flat on the ground but flowering plants lack a rosette and have a flowering stem with leaves and a single green, white and brownish-red flower.

References

↑ "Pterostylis jacksonii". World Checklist of Selected Plant Families (WCSP). Royal Botanic Gardens, Kew.
1 2 Brown, Andrew; Dixon, Kingsley; French, Christopher; Brockman, Garry (2013). Field guide to the orchids of Western Australia : the definitive guide to the native orchids of Western Australia. Simon Nevill Publications. p. 360. ISBN 9780980348149.
1 2 "Pterostylis jacksonii". APNI. Retrieved 26 July 2017.
1 2 "Pterostylis jacksonii". FloraBase . Western Australian Government Department of Parks and Wildlife.

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[WCSP-1] "Pterostylis jacksonii". World Checklist of Selected Plant Families (WCSP). Royal Botanic Gardens, Kew.

[APB-2] 1 2 Brown, Andrew; Dixon, Kingsley; French, Christopher; Brockman, Garry (2013). Field guide to the orchids of Western Australia : the definitive guide to the native orchids of Western Australia. Simon Nevill Publications. p. 360. ISBN 9780980348149.

[APNI-3] 1 2 "Pterostylis jacksonii". APNI. Retrieved 26 July 2017.

[FloraBase-4] 1 2 "Pterostylis jacksonii". FloraBase . Western Australian Government Department of Parks and Wildlife.