Genoplesium sagittiferum

Genoplesium sagittiferum, commonly known as the horned midge orchid and as Corunastylis sagittifera in Australia, is a small terrestrial orchid endemic to New South Wales. It has a single thin leaf fused to the flowering stem and up to ten small, yellowish-green flowers with a hairy reddish labellum.

Horned midge orchid
Scientific classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Monocots
Order: Asparagales
Family: Orchidaceae
Subfamily: Orchidoideae
Tribe: Diurideae
Genus: Genoplesium
Species:
G. sagittiferum
Binomial name
Genoplesium sagittiferum
Synonyms[2]

Description

Genoplesium sagittiferum is a terrestrial, perennial, deciduous, herb with an underground tuber and a single thin leaf 50–100 mm (2–4 in) long and fused to the flowering stem with the free part 10–15 mm (0.4–0.6 in) long. Between two and ten yellowish-green flowers with red streaks are arranged along a flowering stem 5–20 mm (0.2–0.8 in) long and taller than the leaf. The flowers are 6–7 mm (0.2–0.3 in) long and 5–6 mm (0.20–0.24 in) wide and are inverted so that the labellum is above the column rather than below it. The dorsal sepal is egg-shaped, 3–4 mm (0.12–0.16 in) long, 2 mm (0.08 in) wide and pointed with hairless edges. The lateral sepals are linear to lance-shaped, 4–6 mm (0.16–0.24 in) long, about 1.5 mm (0.06 in) wide and spread widely apart from each other. The petals are lance-shaped to egg-shaped, about 3 mm (0.1 in) long, 1 mm (0.04 in) wide and sharply pointed with hairless edges. The labellum is reddish, egg-shaped with the narrower end towards the base, about 3 mm (0.1 in) long, 1 mm (0.04 in) wide, with short hairs on its edges. There is a tapered, dark red callus in the centre of the labellum and extending nearly to its tip. Flowering occurs between February and May.[3][4]

Taxonomy and naming

The horned midge orchid was first formally described in 1942 by Herman Rupp who gave it the name Prasophyllum sagittiferum. The type specimen was collected near Bell by Erwin Nubling[5] and his wife and the description was published in The Victorian Naturalist.[6][7] In 1989, David Jones and Mark Clements changed the name to Genoplesium sagittiferum[1] and in 2002 Jones and Clements changed the name again to Corunastylis sagittifera.[8] The specific epithet (sagittiferum) is from the Latin words sagitta meaning "arrow"[9]:104 and fero meaning "to bear" or "to carry"[9]:187 referring to the arrowhead shape of the labellum callus.[7]

Distribution and habitat

Genoplesium sagittiferum grows with shrubs in sandy soils, sometimes in moss gardens on rock ledges. It is found in the higher parts of the Blue Mountains.[3][4]

References
  1. "Genoplesium sagittiferum". APNI. Retrieved 9 February 2018.
  2. "Genoplesium sagittiferum". World Checklist of Selected Plant Families (WCSP). Royal Botanic Gardens, Kew.
  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. 181. ISBN 1877069124.
  4. Jones, David L. "Genoplesium sagittiferum". Royal Botanic Garden Sydney. Retrieved 9 February 2018.
  5. "Australian Plant Collectors and Illustrators (N)". Council of the Heads of Australian Herbaria. Retrieved 9 February 2018.
  6. "Prasophyllum sagittiferum". APNI. Retrieved 9 February 2018.
  7. Rupp, Hermann (1942). "The section Genoplesium in the genus Prasophyllum". The Victorian Naturalist. 59 (7): 125–126. Retrieved 9 February 2018.
  8. "Corunastylis sagittifera". APNI. Retrieved 9 February 2018.
  9. Brown, Roland Wilbur (1956). The Composition of Scientific Words. Washington, D.C.: Smithsonian Institution Press.
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