Microtis graniticola

Microtis graniticola, commonly known as the granite mignonette orchid[2] or granite onion orchid[3] is a species of orchid endemic to the south-west of Western Australia. It has a single thin, hollow, onion-like leaf and up to sixty small green to greenish-yellow flowers. It grows in soil pockets on granite outcrops, especially where the soil receives run-off during rainy weather.

Granite mignonette orchid
Scientific classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Monocots
Order: Asparagales
Family: Orchidaceae
Subfamily: Orchidoideae
Tribe: Diurideae
Genus: Microtis
Species:
M. graniticola
Binomial name
Microtis graniticola

Description

Microtis graniticola is a terrestrial, perennial, deciduous, herb with an underground tuber and a single erect, smooth, tubular leaf 200–500 mm (8–20 in) long and 5–8 mm (0.2–0.3 in) wide. Between twenty and sixty green to yellowish-green flowers are crowded along a stiff, rigid flowering stem 200–500 mm (8–20 in) tall. The flowers lean downwards and are 4.5–5 mm (0.18–0.20 in) long, 3–3.5 mm (0.12–0.14 in) wide with an ovary 4–5 mm (0.16–0.20 in) long. The dorsal sepal is egg-shaped, 3–3.5 mm (0.12–0.14 in) long, about 2 mm (0.08 in) wide and hood-like. The lateral sepals are oblong, 2–2.5 mm (0.08–0.1 in) long, about 1 mm (0.04 in) wide with their tips rolled downwards. The petals are oblong, about 2 mm (0.08 in) long, 0.5 mm (0.02 in) wide and are enclosed by the dorsal sepal. The labellum is oblong, 3 mm (0.1 in) long, about 1.5 mm (0.06 in) wide and curves downwards with thickened, wavy edges and a notched tip. The callus in the centre of the labellum is variable in shape, but never comma-shaped as in the otherwise similar M. eremicola. Flowering occurs from September to November.[2][3][4][5]

Taxonomy and naming

Microtis graniticola was first formally described in 1996 by Robert Bates from a specimen collected on Wave Rock near Hyden and the description was published in Journal of the Adelaide Botanic Garden.[6] The specific epithet (graniticola) is Latin for "granite dweller", referring to the habitat preference of this species.[4]

Distribution and habitat

Microtis graniticola grows in shallow soil pockets on large granite outcrops in arid areas between Balladonia and Mullewa. Its distribution includes parts of the Avon Wheatbelt, Coolgardie, Geraldton Sandplains, Mallee, Murchison and Yalgoo biogeographic regions.[2][3][4][7]

Conservation

Microtis eremaea is classified as "not threatened" by the Western Australian Government Department of Parks and Wildlife.[7]

References
  1. "Microtis graniticola". World Checklist of Selected Plant Families (WCSP). Royal Botanic Gardens, Kew.
  2. Brown, Andrew; Dundas, Pat; Dixon, Kingsley; Hopper, Stephen (2008). Orchids of Western Australia. Crawley, Western Australia: University of Western Australia Press. p. 287. ISBN 9780980296457.
  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. 225. ISBN 1877069124.
  4. Bates, Robert J. (1996). "Arid land Microtis (Orchidaceae) in Western Australia with the description of three new taxa" (PDF). Journal of the Adelaide Botanic Garden. 17: 120–123. Retrieved 22 February 2018.
  5. Hoffman, Noel; Brown, Andrew (2011). Orchids of South-West Australia (3rd ed.). Gooseberry Hill: Noel Hoffman. p. 341. ISBN 9780646562322.
  6. "Microtis graniticola". APNI. Retrieved 27 February 2018.
  7. "Microtis graniticola". FloraBase. Western Australian Government Department of Parks and Wildlife.
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