Spiranthes australis

Spiranthes australis, commonly known as austral ladies tresses, is a species of orchid that grows from southern Caspian Sea and Himalayan Mountains to the South-West Pacific. It has up to about ten leaves at the base of a flowering stem with up to sixty small pink and white flowers spirally arranged around it.

Austral ladies' tresses
Scientific classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Monocots
Order: Asparagales
Family: Orchidaceae
Subfamily: Orchidoideae
Tribe: Cranichideae
Subtribe: Spiranthinae
Genus: Spiranthes
Species:
S. australis
Binomial name
Spiranthes australis
Synonyms[2]
  • Spiranthes sinensis subsp. australis (R.Br.) Kitam.
  • Spiranthes alticola D.L.Jones
  • Spiranthes sinensis auct. non (Pers.) Ames

Description

Spiranthes australis is a terrestrial, perennial, deciduous, herb with between three and ten linear to lance-shaped or spatula-shaped dark green leaves which are 80–180 mm (3–7 in) long and 6–10 mm (0.2–0.4 in) wide. Between ten and sixty bright pink flowers are crowded and spirally arranged along a flowering spike 250–450 mm (10–20 in) tall. The flowers are 4–5 mm (0.16–0.20 in) long and 3–4 mm (0.1–0.2 in) wide, ranging from deep pink to pure white. The dorsal sepal is lance-shaped to egg-shaped, 4–5 mm (0.16–0.20 in) long and 2.5 mm (0.1 in) wide. The lateral sepals and petals are a similar size to the dorsal sepal but narrower. The labellum is white, has three obscure lobes and is about 6 mm (0.2 in) long. The labellum has a grainy texture and its edges are crinkled. Flowering occurs from October to March or later but the flowers are self-pollinating.[2][3][4]

Flower spike of S. australis in Barrington Tops National Park

Taxonomy and naming

Spiranthes australis was first formally described in 1810 by Robert Brown and the description was published in Prodromus Florae Novae Hollandiae et Insulae Van Diemen.[5][6] The specific epithet (australis) is a Latin word meaning "southern".[7] The taxonomic concept of this species has recently been expanded and its relationship with Spiranthes sinensis clarified.[8]

Distribution and habitat

Austral ladies' tresses usually grows in boggy or swampy places but also in high-rainfall grassy places. It is widely distributed from the southern Caspian Sea of Iran and Georgia (reported as S. amoena, synonym of S. australis)[9] to the southwest Pacific.[8] In Australia, it occurs from Queensland, south through eastern New South Wales, the Australian Capital Territory and Victoria to Tasmania. It is sometimes also found in South Australia.[1][4]

Conservation

Spiranthes australis is common throughout most of its range but is classed as "Rare" in South Australia where it is only known from the Mount Compass area.[3][10]

Use in horticulture

This orchid is relatively easy to grow in a well-drained, sandy potting mix. It sometimes occurs as a weed in commercial nurseries.[11]

References
  1. "Spiranthes australis". World Checklist of Selected Plant Families (WCSP). Royal Botanic Gardens, Kew.
  2. Bernhardt, Peter. "Spiranthes australis". Royal Botanic Garden Sydney. Retrieved 20 January 2018.
  3. Jones, David L. (2006). A complete guide to native orchids of Australia including the island territories. Frenchs Forest, N.S.W.: New Holland. p. 285. ISBN 1877069124.
  4. Jeanes, Jeff. "Spiranthes australis". Royal Botanic Gardens Victoria. Retrieved 20 January 2018.
  5. "Spiranthes australis". APNI. Retrieved 20 January 2018.
  6. Brown, Robert (1810). Prodromus florae Novae Hollandiae et insulae Van-Diemen. London. p. 319. Retrieved 20 January 2018.
  7. Brown, Roland Wilbur (1956). The Composition of Scientific Words. Washington, D.C.: Smithsonian Institution Press. p. 731.
  8. Pace, Matthew C.; Giraldo, Giovanny; Frericks, Jonathan; Lehnebach, Carlos A.; Cameron, Kenneth M. (2019-01-01). "Illuminating the systematics of the Spiranthes sinensis species complex (Orchidaceae): ecological speciation with little morphological differentiation". Botanical Journal of the Linnean Society. 189 (1): 36–62. doi:10.1093/botlinnean/boy072. ISSN 0024-4074.
  9. Akhalkatsi M, Lorenz R, Matchutadze I, Mosulishvili M. (2004). "Spiranthes amoena - a new species for Flora of Georgia". Journal Europäischer Orchideen. 36: 745–754.CS1 maint: multiple names: authors list (link)
  10. "Spiranthes australis" (PDF). Government of South Australia Department for Environment and Heritage. Retrieved 20 January 2018.
  11. "Spiranthes australis". Australian Native Plants Society Australia. Retrieved 20 January 2018.
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