Disperis falcatipetala P.J.Cribb & la Croix, Adansonia, III, 24: 85 (2002).
Description:
A small, terrestrial herb up to 13.5 cm tall. Stem slender bearing three leaves in upper half. Leaves 3, alternate, suberect to spreading, ovate, obtuse, the largest 1.8 × 0.8 cm, the upper two progressively smaller, green with purple markings. Inflorescence terminal, c. 3-flowered; bracts ovate, subacute, 6 × 3 mm. Flowers clustered, white with purple dots; pedicel and ovary up to 10 mm long. Dorsal sepal concave, linearoblong, acute, 4 × 1mm, forming a hood with the petals. Lateral sepals deflexed, obliquely spathulate, obtuse or apiculate, united in basal half to form a narrow claw, 9.5-10 × 3.5 mm. Petals adnate to the dorsal sepal along inner margin, falcate, oblong, truncate, 5 × 1 mm. Lip 3-lobed, 3.5 mm long and wide when spread; side lobes fleshy, arcuate, truncate, villose in apical part; mid-lobe spathulate with an undulate margin to the apical lamina. Column short, 2 mm long including the clavate rostellar arms.
Notes:
Disperis falcatipetala is known only form the type collection which comprises two flowering plants. This small orchid is apparently allied to Disperis lanceolata Bosser & la Croix and to Disperis tripetaloides (Thou.) Lindl. It differs from the former in having slightly larger leaves, a shorter inflorescence, and flowers in which the lateral sepals are united to the middle to form a narrow claw, somewhat truncate petals, and a lip in which the side lobes are as long as the spathulate mid-lobe and villose. The latter differs in having larger more acute leaves and the flower which has free lateral sepals and a lip with a broad hairy base and a narrow, rather than spathulate mid-lobe. Disperis humblotii Rchb.f. has flowers that resemble those of Disperis falcatipetala but the former always has a petiolate lowermost leaf. It is also close to the tropical African Disperis johnstonii Rolfe but that usually has two larger leaves and flowers with a shorter broader claw to the united lateral sepals and a lip in which the mid-lobe is puberulous and has a central umbo.
Habitat:
On a rotten branch on floor in ridge-top montane forest; 1700-1730 m.
Distribution:
N. Madagascar
