Australian Tropical Rainforest Orchids
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Phaius australis

Common Swamp Orchid

Phaius australis F.Muell., Fragm. 1: 42 (1858). Type: Lady Elliots Island off Wide Bay, 1857, E. Fitzalan s.n. (holo MEL!).

Phaius carronii F.Muell., Essay Pl. Exped. Burdekin 19, in obs (1860). Type: Burdekin Expedition, [Fitzalan?] (holo MEL!).

Phaius leucophaeus F.Muell., Fragm. 4: 163 (1864). Type: In locis scaturiginosis valde umbrosis silvarum circum sinum Rockingham Bay, J. Dallachy s.n. (holo MEL).

Phaius grandifolius var. bernaysii soutterii F.M.Bailey, Queensl. fl. 5: 1544 (1902); Phaius bernaysii forma soutteri (F.M.Bailey) T.E.Hunt, Census South Queensland Orchids 12 (1947). Type: Islands of Moreton Bay, W. Soutter s.n. (holo BRI not found).

Phaius grandifolius var. rowanae F.M.Bailey, Queensland Agric. J. 28: 74 (1912). Type: Murray River, North Queensland, F.C. Rowan s.n. (icon BRI not found).

Distribution

Occurs in Queensland from near Cooktown to Lake Cathie, south of Port Macquarie, in New South Wales.

Altitude: 5-1100 m.

Also occurs in Fiji, Wallis and Futuna, Indonesia, New Caledonia, New Guinea, the Solomon Islands and Vanuatu.

Description

Terrestrial herb forming large clumps. Pseudobulbs crowded, ovoid, 5-7 cm x 5-7 cm. Leaves 4-7, erect, apical, petiolate; lamina lanceolate, 50-125 cm x 8-10 cm, dark green, pleated, thin-textured, apex acute to acuminate. Inflorescence an axillary raceme, 500-2000 mm tall, robust, with numerous bracts along the stem. Flowers 4-16, resupinate, porrect to nodding, star-shaped, 60-100 mm x 65-110 mm, reddish brown internally, sometimes with yellowish veins, white externally. Sepals and petals fleshy, apices acuminate. Dorsal sepal obliquely erect, 45-55 mm x 12-16 mm. Lateral sepals free, widely divergent, 45-55 mm x 15-20 mm. Petals 45-50 mm x 12-15 mm. Labellum 50-60 mm x 40-45 mm, 3-lobed; lateral lobes ranging from tightly tubular around column to spreading away from column; midlobe with crinkled or undulate margins; basal spur 5-10 mm long, narrow. Callus a narrow raised plate. Column 17 mm long, dilated towards apex, sparsely covered in short hairs. Column foot absent. Capsules pendulous, dehiscent.

Ecology

Occurs in swamps, especially those dominated by Broad-leaved Paper Bark (Melaleuca quinqenervia), where it forms spreading colonies. It is also found in open forests and wallum growing among grass and shrubs in depressions and localised seepage areas, forming small isolated colonies. An extremely variable species with some forms having widely opening flowers, and others expanding tardily. The degree of incurvature of the labellum margins is also highly variable within the species.

Widespread and locally common.

Flowering period: September-November.

Notes

Records from Australia attributed to P. tancarvilliae can usually be traced to cultivated plants of the exotic P. wallichii or variants of P. australis in which labellum margins extend above column.

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