Phaius amboinensis

Arnhem Land Swamp Orchid

Phaius amboinensis Blume, Mus. Bot. 2: 180 (1856). Type: In Amboina, Zippel s.n. (lectotype L), fide Ormerod (1994).

Angraecum terrestre alterum Rumph., Herb. Amboin. 6: 113-114, t. 52, f. 1 (1750), nom. illeg., pre 1753.

Bletia amboinensis Zipp. Ex Blume, Mus. Bot. Lugd.-Bat. 2: 179 (1859), nom.

Phaius graeffei Rchb.f. in Seem., Fl. Vitiensis 299 (1868). Type: Samoa, Upolu Islands, 2000 ft., Graeffe s.n. (holo W).

Phaius papuanus Schltr. in K.Schum. & Laut., Fl. Schutzg. Sudsee, Nachtr. 165 (1905); Phaius amboinensis var. papuanus (Schltr.) Schltr., Repert. Spec. Nov. Regni Veg., Beih. 1: 375 (1911) & Fig. Atlas. t. 132, f. 496 (1928). Type: Kaiser-Wilhelms-Land: In humus of the forests at the foot of the Torricelli Range, alt. c. 100 m, Apr.1902, R. Schlechter 14595 (holo B).

Phaius neocaledonicus Rendle, J. Proc. Linn. Soc., Bot. 45: 249 (1921). Type: New Caledonia, Compton 1408 (holo BM).

Phaius terretris sensu (L.) Ormerod, Austral. Orchid Rev. 59(2): 14 (1994) (sic ‘terrestre’).

Distribution

Found at the headwaters of the Habgood River in the Northern Territory.

Altitude: 250-300 m.

Also occurs in Fiji, Indonesia, New Caledonia, New Guinea, the Solomon Islands and Somalia.

Description

Terrestrial herb forming large clumps. Stems 3-4, crowded, cylindrical to angular, 40-80 cm x 1.5-2 cm, slender, fleshy. Leaves 3-8, scattered along stem, erect, whorled, petioles to 15 mm long, bases sheathing stem; lamina lanceolate, 40-80 cm x 7-14 cm, dark green, pleated, thin-textured, apex acute to acuminate. Inflorescence an axillary raceme, 300-900 mm long, from lower nodes on stem, tough. Flowers 5-20, resupinate, porrect to nodding, star-shaped, 40-70 mm x 42-75 mm, white with yellow labellum. Dorsal sepal obliquely erect, narrowly elliptic to oblong, 30-35 mm x 7-8 mm. Lateral sepals free, divergent, 30-35 mm x 8-10 mm. Petals widely spreading, recurved, 30-35 mm x 6-8 mm. Labellum 25-30 mm x 20-25 mm, with scattered long white hairs, 3-lobed; basal margins incurved; apical margins undulate. Callus with 2 narrow parallel central plates ending in series of overlapping blunt structures. Column 20 mm long, moderately dilated towards apex. Column foot absent. Capsules pendulous, dehiscent.

Ecology

Occurs in forests in deep shade, growing in spring-fed swampy clay soil with deep black humus layer.

Highly localised.

Flowering period: August-November.

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