Thrixspermum ravanii Cootes & Tiong ex Sodusta & Cootes

Sodusta, Patrick Jason A. & Cootes, Jim, 2024, Validation of Thrixspermum ravanii (Aeridinae, Orchidaceae), a new species from the Philippines, Phytotaxa 661 (2), pp. 211-212 : 211

Thrixspermum ravanii Cootes & Tiong ex Sodusta & Cootes , sp. nov.

Diagnosis:—The proposed new species is closely related to Thrixspermum robinsonii Ames (1915: 207) but differs by much larger plant dimensions, and having flowers which are considerably smaller than those of T. robinsonii . It also differs in the triangular shape of the side lobes, and the oblanceolate shape of the petals.

Type:— PHILLIPPINES. Mindoro Island: Oriental Mindoro Province, Municipality of Puerto Galera. From a material cultivated by Ravan Schneider originating from Mt. Talipanan in Northern Mindoro, September 2011 (holotype: NSW902484 !)

Epiphytic, upright, monopodial. Stems terete; up to 16 cm tall, occasionally branching. Leaves leathery, alternate, narrowly oblong, unequally lobed at the apex, upper surface channeled; up to 12 cm long, 1.8 cm wide, bright green. Inflorescences semi-erect, becoming pendulous with age, equal or longer than the leaves, smoothly surfaced. Peduncle about 1.3 mm in diameter; with one triangular bract, positioned centrally. Rachis congested, flowers produced successively around the rachis, with only one bloom opened at any time, flowers short-lived. Floral bracts triangular to 3 mm long by 1.3 mm wide. Plants flower 5 to 6 times a year. Sepals and petals white with a dull orange apex, and reddish brown to purplish stripes internally. Callus orange. Flowers about 8 mm across and they do not open widely. Dorsal sepal ovate, 4 mm long, 2 mm wide, hooded, apex rounded. Petals oblanceolate, 3.5 mm long, 1.75 mm wide; curving inwards, apex rounded. Lateral sepals broadly ovate, 4.5 mm long, 2.5 mm wide; ridged on back; apex obtusely pointed. Labellum rigidly attached to column; saccate at base, sac about 3 mm long, 2 mm wide, bearing a squarish callus at the opening of the sac; edges and internal surface bearing minute hairs, apex of sac bilobed; no midlobe. Side lobes triangular, pointing forward, 2 mm long. Pedicel and ovary 6 mm long, 0.5 mm in diameter. Column very short, about 1.5 mm long.