Pterostylis areolata

Greenhood
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Monocots
Order:	Asparagales
Family:	Orchidaceae
Genus:	Pterostylis
Species:	P. areolata
Binomial name
	Pterostylis areolata; Petrie [1]

Last updated May 03, 2019

Pterostylis areolata is a species of orchid endemic to New Zealand. 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. This greenhood has green and translucent white-striped flowers similar to those of P. australis but the stem leaves are shorter and never higher than the flowers.

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.

New Zealand is a sovereign island country in the southwestern Pacific Ocean. The country geographically comprises two main landmasses—the North Island, and the South Island —and around 600 smaller islands. New Zealand is situated some 2,000 kilometres (1,200 mi) east of Australia across the Tasman Sea and roughly 1,000 kilometres (600 mi) south of the Pacific island areas of New Caledonia, Fiji, and Tonga. Because of its remoteness, it was one of the last lands to be settled by humans. During its long period of isolation, New Zealand developed a distinct biodiversity of animal, fungal, and plant life. The country's varied topography and its sharp mountain peaks, such as the Southern Alps, owe much to the tectonic uplift of land and volcanic eruptions. New Zealand's capital city is Wellington, while its most populous city is Auckland.

Pterostylis australis, commonly known as the southern greenhood, is a species of orchid endemic to New Zealand. Unlike many other greenhood orchids, this species lacks a rosette of leaves but instead only has leaves on the flowering stem. The leaf's shape differs according to it position on the stem and there is a single green and white-striped flower. This greenhood occurs on both of the main islands of New Zealand and often forms large colonies.

Description

Pterostylis areolata is a terrestrial, perennial, deciduous, herb with an underground tuber and when not flowering, one or two egg-shaped leaves, 30–90 millimetres (1–4 in) long and 10–25 millimetres (0.4–1 in) wide. Flowering plants usually have a single pale green flower with translucent white stripes, sometimes with orange-coloured tips. The flowers are relatively large, lean forwards and are borne on a flowering stem 70–250 millimetres (3–10 in) high with between two and four stem leaves. The dorsal sepal and petals are fused, forming a hood or "galea" over the column with the dorsal sepal having a short point on its end. The lateral sepals spread apart from each other and turn towards the back of the galea. The labellum is red becoming darker near the tip. Flowering occurs from October to December.^[2]^[3]

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 areolata was first formally described in 1968 by Donald Petrie and the description was published in Transactions and Proceedings of the New Zealand Institute from a specimen collected near the Awatere River.^[1]^[4] The specific epithet (areolata) is a Latin word meaning "with small spaces".^[5]

Donald Petrie was a Scottish botanist noted for his work in New Zealand.

The Awatere River is a large river flowing through Marlborough, New Zealand. Flowing along the trace of the active Awatere Fault, it runs northeast through a straight valley to the west of the Inland Kaikoura mountains. This valley is parallel with that of the Clarence River, 20 kilometres (12 mi) to the south.

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

This greenhood grows in tussock grassland and scrub, near wetlands and in open forest. It occurs on both main islands of New Zealand, in a few places on the North Island but is widespread, especially on the eastern side of the South Island.^[2]^[3]

Tussock grasslands form expansive and distinctive landscapes in the South Island and to a lesser extent in the central plateau region of the North Island of New Zealand. Most of the plants referred to as tussocks are in the genera Carex, Chionochloa, Festuca, and Poa.

The North Island, also officially named Te Ika-a-Māui, is one of the two main islands of New Zealand, separated from the larger but much less populous South Island by Cook Strait. The island's area is 113,729 square kilometres (43,911 sq mi), making it the world's 14th-largest island. It has a population of 3,749,200.

The South Island, also officially named Te Waipounamu, is the larger of the two major islands of New Zealand in surface area; the other being the smaller but more populous North Island. It is bordered to the north by Cook Strait, to the west by the Tasman Sea, and to the south and east by the Pacific Ocean. The South Island covers 150,437 square kilometres (58,084 sq mi), making it the world's 12th-largest island. It has a temperate climate.

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Pterostylis banksii, commonly known as greenhood or tutukiwi, is a species of orchid endemic to New Zealand. Non-flowering plants have a rosette of leaves. Flowering plants have leaves on the flowering stem, some of which reach above the single relatively large, green flower with translucent white stripes. It is the most common, widespread and largest New Zealand greenhood and is found on both of the main islands.

Pterostylis agathicola, commonly known as the kauri greenhood, is a species of orchid endemic to the North Island of New Zealand. 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. It grows almost exclusively in kauri forest and has a relatively large green and transparent white flower.

Pterostylis alobula, commonly known as the winter greenhood, is a species of orchid endemic to New Zealand. 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. This greenhood has pale green and white-striped flowers, similar to those of another New Zealand greenhood, P. trullifolia but are larger and paler in colour.

Pterostylis auriculata is a species of orchid endemic to New Zealand. Unlike many other greenhood orchids, this species lacks a rosette of leaves but instead only has leaves on the flowering stem. All parts of the plant are glossy and there is a single green flower with a reddish tinge.

Pterostylis brumalis, commonly known as the kauri greenhood or winter greenhood, is a species of orchid endemic to New Zealand. There is a rosette of leaves at the base of both flowering and non-flowering plants. Flowering plants have a white flower with narrow green stripes and a dorsal sepal which bends forward strongly while the petals spread widely, giving the flower a cobra-like appearance.

Pterostylis cernua, commonly known as the Westland greenhood, is a species of orchid endemic to New Zealand. Non-flowering plants have a rosette of leaves but flowering plants have a single white, dark green and reddish-brown flower with leaves on the flowering stem.

Pterostylis humilis is a species of orchid endemic to New Zealand. It has a rosette of leaves at the base of the plant and when flowering stem, leaves which usually obscure the dark green and white flower.

Pterostylis irsoniana is a species of greenhood orchid endemic to New Zealand. There are up to five erect leaves on the flowering stem with a single dark green flower with white stripes and a reddish tinge on the tips. It has a distinctive curved labellum with a curled tip with a dark red callus.

Pterostylis irwinii is a species of greenhood orchid endemic to New Zealand. Flowering plants have erect, linear leaves on the flowering stem while non-flowering plants have a rosette of egg-shaped leaves. There is a single green flower with translucent white stripes and reddish-brown tips.

Pterostylis micromega, commonly known as the swamp greenhood, is a species of greenhood orchid endemic to New Zealand. Both flowering and non-flowering plants have a rosette of leaves while flowering plants also have a single, relatively large whitish flower with a pointed dorsal sepal. The flower colour and pointed dorsal sepal are unique in New Zealand Pterostylis.

Pterostylis montana is a species of greenhood orchid endemic to New Zealand. Flowering plants have erect, linear leaves on the flowering stem with a single green flower with translucent white stripes and an unusual twisted labellum.

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Pterostylis patens is a species of greenhood orchid endemic to New Zealand. Flowering have plants spreading leaves on the flowering stem and a single green and white flower with spreading, tapering lateral sepals.

Pterostylis puberula, commonly known as the dwarf greenhood or snail greenhood is a species of orchid which is endemic to New Zealand. It has a rosette of pale yellowish, stalked leaves and a single silvery-white and green flower with relatively long, erect lateral sepals.

Pterostylis silvicultrix, commonly known as the Chatham Island greenhood or tutukiwi, is a species of orchid which is endemic to Chatham Island and nearby islands. Non-flowering plants have a rosette of leaves but flowering plants have leaves on the flowering stem, some of which reach above the single translucent white flower with dark green stripes. It is similar to Pterostylis banksii which occurs on both of the main islands of New Zealand but that species lacks the orange or reddish-brown tips on the flowers of this species.

Pterostylis tasmanica, commonly known as the small bearded greenhood, is a species of orchid in the family Orchidaceae which is native to south-eastern Australia and New Zealand. It has a single green flower with translucent "windows" and a long, thin labellum bordered with golden hairs. It is similar to P. plumosa but is shorter, with smaller leaves and flowers but a more densely feathery labellum.

Pterostylis tristis, commonly known as the midget greenhood, is a species of greenhood orchid endemic to New Zealand. Both flowering and non-flowering plants have a rosette of fleshy leaves lying flat on the ground and flowering plants have up to eight yellowish-green or brownish flowers with pale stripes.

Pterostylis venosa, commonly known as a greenhood, is a species of orchid endemic to New Zealand and which usually grows in colonies. Both flowering and non-flowering plants have a rosette of erect to spreading leaves, and flowering plants have a single yellowish-green to dark green flower with white stripes. It is similar to P. humilis.

Pterostylis divaricata is a species of orchid endemic to northern New South Wales. It grows in colonies of genetically identical plants. As with similar orchids, plants in flower differ from those that are not. Those not in flower have a rosette of leaves that lie flat on the ground. Plants in flower lack a rosette at the base but have up to ten translucent white flowers with green and brown stripes. This greenhood is similar to P. striata but has larger flowers and a longer tip on the dorsal sepal.

References

1 2 "Pterostylis areolata". World Checklist of Selected Plant Families (WCSP). Royal Botanic Gardens, Kew.
1 2 de Lange, Peter James. "Pterostylis areolata". New Zealand Plant Conservation Network. Retrieved 16 June 2017.
1 2 "Pterostylis areolata". New Zealand Native Orchid Group. Retrieved 16 June 2017.
↑ Petrie, Donald (1917). "Description of new native flowering plants". Transactions and Proceedings of the New Zealand Institute. 50: 210–211. Retrieved 16 June 2017.
↑ Brown, Roland Wilbur (1956). The Composition of Scientific Words. Washington, D.C: Smithsonian Institution Press. p. 100.

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[WCSP-1] 1 2 "Pterostylis areolata". World Checklist of Selected Plant Families (WCSP). Royal Botanic Gardens, Kew.

[NZPCN-2] 1 2 de Lange, Peter James. "Pterostylis areolata". New Zealand Plant Conservation Network. Retrieved 16 June 2017.

[NZNOG-3] 1 2 "Pterostylis areolata". New Zealand Native Orchid Group. Retrieved 16 June 2017.

[Petrie-4] Petrie, Donald (1917). "Description of new native flowering plants". Transactions and Proceedings of the New Zealand Institute. 50: 210–211. Retrieved 16 June 2017.

[RWB-5] Brown, Roland Wilbur (1956). The Composition of Scientific Words. Washington, D.C: Smithsonian Institution Press. p. 100.