Australian Tropical Rainforest Orchids
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Crangonorchis depauperata

Keeled Greenhood

Crangonorchis depauperata (F.M.Bailey) D.L.Jones & M.A.Clem., Austral. Orch. Res. 4: 71 (2002).

Pterostylis depauperata F.M.Bailey, Bot. Bull. Dept. Agric. Queensland 4: 18 (1891). Type: Queensland. Near Cairns, 1890, C.J. Wild s.n. (lecto BRI), fide Clements (1989).

Pterostylis carinata Dockrill, North Queensland Naturalist 23(110): 4-5, fig. (1955). Type: Queensland. Ravenshoe District, North Queensland, 16 April 1954, W.W. Abell and W.G. McPherson s.n. (holo NSW).

Distribution

Occurs in north-eastern Queensland from Mount Finnigan near Cooktown to Ravenshoe.

Altitude: 500-900 m.

Description

Terrestrial herb forming clonal colonies. Tubers globose, fleshy. Leaves 3-7, forming a basal rosette, prostrate, ground-hugging, shortly petiolate; lamina ovate to oblong, 1-4 cm x 0.5-2 cm, greyish green, apex obtuse. Inflorescence terminal, single-flowered, 80-200 mm tall, peduncle arising from centre of rosette, very thin, wiry. Flower solitary, resupinate, erect, hooded, 15-17 mm x 8-10 mm, white with lime green striations. Dorsal sepal and petals adherent, forming hooded galea. Dorsal sepal large, curved forward in a semi-circle, 10-13 mm long, apex caudate. Lateral sepals erect, bases fused to form synsepalum for proximal third; sinus broad, flat, shallowly emarginate; distal parts divergent, free points erect above galea, 17-21 mm long, caudate. Petals oblong, falcate, 15 mm x 5 mm, apex acute. Labellum unlobed, just protruding when set, 8-10 mm x 3 mm, curved, dark brown, bluntly acuminate. Column entirely enclosed within galea, lower wings broad, anterior surface sparsely ciliate, 2 stelidia extending above anther. Column foot shorter than column. Capsules erect, dehiscent.

Ecology

Occurs in open forests, woodlands and rainforest margins on sheltered slopes. It is found growing in amongst grass and shrubs in well-drained sandy or gravelly soil. The plants are deciduous and survive as tubers for the drier part of the year. They re-emerge with summer rains, flowering throughout autumn and into winter. The flowers are pollinated by small gnats. It reproduces by seed and spreads clonally through the production of daughter tubers at the ends of roots.

Locally common.

Flowering period: March-August.

Name Changes

Until recently known as Pterostylis depauperata.

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