Cadetia citrina

Cadetia citrina (Ridl.) Schuit., Blumea 39 (1994) 235.

Basionym: Dendrobium citrinum.

Roots to more than 12 cm long, 0.5-1 mm diameter. Rhizome very short. Pseudobulbs crowded, cylindrical to narrowly fusiform, weakly 4-ribbed, 10-25 mm long, 2-3 mm diameter. Leaf elliptic-oblong to broadly lanceolate, index 1.75-6.25, 1-3.2 cm by 4-8 mm, base cuneate to subpetiolate, apex obtuse, minutely bilobulate, mucronate, mucro longer than lobules. Inflorescences terminal from the leaf axil and subterminal just below the abaxial side of the leaf, solitary, rarely 2 in succession from the same position, at the base with a 4-6 mm long tubular sheath. Peduncle 4-6 mm long. Ovary and pedicel 2-4 cm long, 6-winged, glabrous. Flower large for the genus, 1.5-2.5 cm across. Median sepal patent to reflexed, elliptic-ovate, 6-11 by 3.2-4.5 mm, obtuse, 5-nerved. Lateral sepals patent, elliptic to broadly elliptic, 8-13.8 by 4.8-5.7 mm, obtuse, 5-nerved; mentum narrowly cylindrical, semicircular incurved, 7-10 by 1 mm, apical closed part 6.4-9 mm, apex rounded. Petals porrect, obliquely elliptic, 3.9 - 4.7 by 1.8 - 2.8 mm, entire, acuminate, apical half reflexed, 1-nerved. Lip narrowly spathulate, 3-lobed, glabrous; hypochile clawed, the claw narrowly linear, 8.3-13.5 by 0.7-1 mm, the blade 3.1-4.9 by 3-3.2 mm; lateral lobes obliquely broadly ovate, 1.4-2 by 1.2-1.3 mm, entire, rounded, at the base joined by a transverse horizontal emarginate lamella, creating a shallow cavity; midlobe broadly ovate to suborbicular, 2.8-3.5 by 2-2.3 mm, entire, apex abruptly acuminate; callus oblong, minutely papillose, extending from the base of the lateral lobes to about halfway the midlobe, in front 3-ribbed, the median rib drawn out in a low narrow crest extending to just below the apex of the midlobe. Column 1.8-3.6 mm long, glabrous, wings semiquadrate, obscurely bidentate, clinandrium entire, with a narrow triangular median tooth; foot 7-10 mm long, pubescent at the base. Anther suborbicular, base emarginate, 0.9 by 0.9 mm, glabrous; pollinia 0.8 mm long. Fruit ovoid, c. 10 by 5 mm, 4(!)-winged.

Colours: Leaves dull dark green above, pale green below. Flower pure white, sometimes yellowish cream (when old?), callus usually yellowish green to bright yellow, anther green.

Habitat: Epiphyte on mossy tree trunks and logs in primary montane forest. Altitude 1250 to 2000 m.

Flowering time in the wild: April-July, November, December.

Distribution: New Guinea (endemic).

Distribution in New Guinea: Papua (Sorong, Manokwari, and Jaya Wijaya Regencies), Papua New Guinea (Madang, Enga and Southern Highlands Provinces).

Map: CITRIMAP.JPG [Cadetia citrina (Ridl.) Schuit., distribution map.]

Notes: Cadetia citrina has the largest flowers in the genus. It is most similar to Cadetia cyclopensis, but is easily distinguished by the petals being only about half as long as the sepals and by the broadly rounded instead of triangular sidelobes of the lip, which are at the base joined by a transverse lamella.

Cultivation: Cool growing epiphyte, prefers light shade and excellent drainage but also nearly constant high humidity.