Phalaenopsis rosenstromii F.M.Bailey, Queensland Agric. J. 17: 231 (1906); Phalaenopsis amabilis var. rosenstromii (F.M.Bailey) Nicholls, Austral. Orchid Rev. 14: 104 (1949). Type: On trees, high from the ground, Daintree River, G. Rosenstrom s.n. (holo K; iso BRI).
Occurs in north-eastern Queensland from Iron Range to Mt Spec.
Altitude: 200-500 m.
Epiphytic or lithophytic herb forming semi-pendulous clumps. Plants usually consisting of single growth with long thick flat roots. Stems 10-30 cm long. Leaves 2-8, crowded, scattered along stem, pendulous, distichous, alternate, sessile, bases sheathing stem and imbricate; lamina oblong to obovate, 15-30 cm x 4-7 cm, thick, fleshy, dark green, apex unequally emarginate. Inflorescence an axillary panicle, arching, 300-750 mm long, stiff, sparsely branching near apex; pedicels 20-30 mm long. Flowers 2-10 per branch, resupinate, porrect, star-shaped, 60-70 mm x 50-80 mm, nearly flat, white. Sepals and petals spreading widely, petals wider than sepals. Dorsal sepal ovate, erect, 30-40 mm x 20 mm, narrow at the base. Lateral sepals free, divergent, ovate, 30-40 mm x 20 mm. Petals very broad, 30-40 mm x 30-40 mm. Labellum 25 mm long, white with yellow and red-brown streaks and bars, 3-lobed; lateral lobes incurved, 15-20 mm x 10-13 mm, white; midlobe 16 mm long, tapered, apex with 2 curved filiform appendages. Callus yellow with red-brown markings. Column 7 mm long. Column foot 5 mm long, at right-angles to the column. Capsules porrect, dehiscent.
Occurs in rainforests in humid airy situations on sheltered slopes and in gullies, in deep gorges and close to waterfalls and streams, growing on trees, rarely rocks. The attractive flowers are long-lived and the panicles can stay green and produce secondary inflorescences for 2-3 years.
Flowering period: December-April.