Australian Tropical Rainforest Orchids
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Rhinerrhiza divitiflora

Raspy Root Orchid

Rhinerrhiza divitiflora (F.Muell. ex Benth.) Rupp, Victorian Naturalist 67: 206 (1951). Sarcochilus divitiflorus F.Muell. ex Benth., Fl. Austral. 6: 292 (1873); Thrixspermum divitiflorum (F.Muell. ex Benth.) Rchb.f., Gard. Chron. (new ser.), 7: 750 (1877). Type: ‘Macleay River’, 1870, R.D. Fitzgerald s.n. (holo K; iso NSW, W).

Thrixspermum freemanii> Rchb.f., Gard. Chron. (new ser.), 7: 750 (1877); Sarcochilus freemanii Rchb.f., Gard. Chron. (new ser.), 7: 750 (1877); Rhinerrhiza freemanii (Rchb.f.) Garay, Bot. Mus. Leafl. 23 (4): 194 (1972). Type: cult. Chelsea, London, W. Bull 2081 (holo W).

Distribution

Occurs in Queensland from the Atherton Tableland, south to the Hunter River in New South Wales.

Altitude: 0-1200 m.

Description

Epiphytic or lithophytic herb forming small clumps. Plants usually consisting of a single stiffly projecting growth. Stems short, erect to semi-pendulous. Roots numerous, appressed to host, broad, flat, 0.5 cm wide, grey, raspy. Leaves 2-6, crowded along stem, prostrate to pendulous, distichous, alternate, sessile, bases sheathing stem, imbricate; lamina oblong, 8-15 cm x 2.5-3 cm, dark green, thin-textured but stiff, almost parchment-like, margins undulate, apex uncinate, unequally emarginate. Inflorescence an axillary raceme, arching to pendulous, 200-300 mm long, stiff. Flowers 10-60, resupinate, porrect, star-shaped, lasting 1-2 days, opening in sporadic groups, 40-50 mm x 40-50 mm, yellow to orange with red blotches and white labellum. Sepals and petals widely spreading, narrow, tapering, apices filiform. Dorsal sepal 35-50 mm x 2 mm. Lateral sepals free, 35-50 mm x 2 mm. Petals 30-45 mm x 2 mm. Labellum hinged to column foot, projecting forwards, 4 mm x 3 mm, 3-lobed; lateral lobes erect, 3.5 mm x 2.5 mm, with numerous irregular red stripes; midlobe short, obtuse; spur short, obtuse. Column 2 mm long. Column foot 2 mm long, at an acute angle to column. Capsules porrect, dehiscent.

Ecology

Occurs in rainforests and in gorges, gullies and moist humid areas in open forest. It grows predominantly on trees, less commonly on rocks. In the tropics it is confined to the ranges and tablelands, but further south it occurs at lower altitudes. The flowers are attractive but short-lived, usually opening in groups along the raceme. Plants in an area often flower synchronously.

Widespread and common.

Flowering period: August-November.

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