Australian Tropical Rainforest Orchids
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Nervilia aragoana

Tall Shield Orchid

Nervilia aragoana Gaud. in Freycinet, Voy. Uranie 422, t. 35 (1829). Type: Guam, Gaudichaud s.n. (holo P).

Pogonia flabelliformis Lindl. in Buch., Wall. Cat. n. 7400 (1832), nom. nud.; Epipactis flabelliformis Ham. in Buch., Wall. Cat. n. 7400A (1832), nom. nud.;Aplostellis flabelliformis (Lindl.) Ridl., Fl. Malay Pen. 4: 203 (1924); Nervilia flabelliformis (Lindl.) Tang & Wang, Act. Phytotax. Peking 1 (1): 68 (1951). Type: Nepal, Sukanagar, 13 June 1810, Hamilton 1942 ex Wallich 7400A (holo K; iso E).

Epipactis carinata Roxb., Fl. Indica 3: 454 (1832); Pogonia carinata (Roxb.) Lindl., Gen. sp. orchid. pl. 414 (1840); Nervilia carinata (Roxb.) Schltr., Bot. Jahrb. Syst. 45: 404 (1911). Type: Bengal, Bengalia, presumably Serampore, Voigt s.n. (holo C).

Pogonia nervilia Blume, Mus. Bot. 1: 32 (1849). Type: Timor, Lesser Sunda Island, Zipp s.n. (holo L).

Pogonia gracilis Blume, Coll. Orch. Arch. Ind. 155, t. 57 (1858). Type: Java, Waitz s.n. (holo L).

Pogonia scottii Rchb.f., Flora 55(18): 276 (1872); Nervilia scottii (Rchb.f.) Schltr., Bot. Jahrb. Syst. 45: 404 (1911). Type: Darjeeling Himalaya, Scott s.n. (holo W).

Nervilia yaeyamensis Hayata, Icon. pl. Formos. 2: 140 (1912). Type: Yaeyama, July1910, Ishigakishima s.n. (holo TAI?).

Nervilia tibetensis Rolfe, Notes Roy. Bot. Gard. Edinburgh 8: 128 (1913). Type: China, Yunnan, Chumutang, Salween River, Kingdon-Ward 151 (holo K).

Distribution

Occurs in the northern parts of the Northern Territory and in far north-eastern Queensland on the McIlwraith Range.

Altitude: 0-150 m.

Also occurs in New Guinea and New Caledonia and apparently has an extensive distribution throughout south-east Asia and into India.

Description

Terrestrial herb forming clonal colonies. Sterile plants a solitary leaf only. Fertile plants initially a terminal inflorescence, a single leaf arising later from base of scape. Tubers solitary, fleshy, rounded, 1.5-3.5 cm wide. Leaf solitary, erect to prostrate, apical, petiole 15-20 cm long; lamina ovate to reniform, appearing circular, 15-25 cm wide, concave, bright green, with prominent radiating veins, margins undulate, erect; basal margins overlapping or infolded; apex apiculate. Inflorescence a terminal raceme, 200-350 mm long, green, fleshy; peduncle elongating in fruit; pedicels 8-10 mm long, not elongating in fruit. Flowers 2-6, resupinate, porrect to nodding, star-shaped, 35-40 mm x 30-35 mm, pale green with cream, yellowish or greenish labellum. Sepals and petals narrowly lanceloate, spreading widely. Dorsal sepal erect, 17-24 mm x 2-2.5 mm. Lateral sepals free, divergent, 17-24 mm x 2-2.5 mm. Petals spreading, 14-20 mm x 2 mm. Labellum 17-22 mm x 9-12 mm, with a filigree of hairy purple or green veins, 3-lobed; lateral lobes incurved; midlobe with irregular undulate margins and 3 hairy ridges. Column 6-10 mm long, wider towards apex. Column foot absent. Capsules pendulous, dehiscent.

Ecology

Occurs in tall rainforests and monsoonal rainforests where it grows along streams in black peaty soil. Plants are dormant and leafless throughout the dry season, surviving as subterranean tubers. Growth commences with the first soaking rains of the wet season when the inflorescence alone is produced. The flowers are short-lived and the inflorescence lengthens as the capsules develop. Leaves appear following fruiting when the seeds have dispersed and the flowering stem has collapsed.

Highly localised.

Flowering period: September-December.

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