Bulbophyllum contortum Z.Zhou, P.Y.Wu & Z.J.Liu, sp. nov. (ffifflƃāä; Figs 1, 2)

Type:— CHINA, Zhenyuan, Yunnan, epiphytic on branches in forests, 2100 m, 12 Oct 2017, cultivated and flowered in Wenzhou, 10 Apr 2020, Zhou 2020041001 (holotype: ZM!).

This new species is similar to B. lemniscatoides Rolfe (1890: 672) and B. lemniscatum Parish in Hooker (1872: 5961), but it differs in shape and size of its pseudobulbs, inflorescence shape, flower colour and shape and size of the sepalar appendages (Table 1).

Epiphytic herbs with a creeping rhizome. Pseudobulbs subglobose, 8.5–15.5 mm in diam., often somewhat irregularly depressed when old, yellowish green, when young covered by white sheaths breaking up in a polygonal pattern,each pseudobulb with2 apical leaves.Leaf deciduous at anthesis, subsessile; blade pale green, broadly lanceolate, 2.6–8.5 × 0.4–1.6 cm, apex acute. Scape arising from base of leafless pseudobulb, 4–10 cm, with two sheaths below the middle, slightly inflated above the middle; raceme pendulous from the curved tip of the scape, 2–4 cm, densely many- flowered; floral bracts 3.5–4.7 mm, apex acute. Pedicel and ovary ca. 2–3 mm, with sparse purple-red hairs near the apex. Flowers purplish red. Sepals ovate-triangular, concave, 1.5–2.0 × 1.0– 1.5 mm, obtuse, 4-grooved, purplish red, green at the base, glossy inside, outside with dense papillae and sparse purple-red hairs, appendages situated on the back of each sepal just below the apex, 6.0–10.0 mm long, 0.2–0.3 mm in diam., with 5–8 flanges contorted from a light cream-purple capillary axis, consisting of longitudinal crenate undulate white and cream-purple plates, gradually narrowed into capillary with fine papillae at base, lateral sepals adnate to column foot, their lower edges connate to each other, entire, acute. Petals included, linear-lanceolate, obtuse, longer than and appressed to the column, white with purple veins, ca. 1.2–1.4 × 0.5 mm, margin entire, apex acute; lip ligulate, ca. 1.5 × 1.0 mm, recurved, with dense fine papillae, dark-red purple, with V-shaped concavity on upper surface, base attached to end of column foot by an immobile joint, margin decurved. Column ca. 1.2 mm; foot ca. 1 mm; stelidia narrowly lanceolate, white with sparse red spots; anther cap hemispherical, densely and minutely papillate, white with sparse red spots. Pollinia 4, in 2 pairs.

Phenology:— Flowering March–April.

Etymology:— Referring to the contorted flanges of sepalar appendages.

Distribution and habitat:— So far known only from the type locality, where it is epiphytic on trees at 2100 m in evergreen, broad-leaved forests.

Conservation status:— A single population is known thus far. The number of mature individuals in the population is less than 50 plants. According to the World Conservation Union Red List Categories and Criteria version 3.1 (IUCN, 2001), we suggest that the unofficial conservation status of this new species should be CR (critically endangered).

Notes: —The two deciduous leaves and floral morphology of this new orchid indicate that this species belongs to Bulbophyllum section Lemniscata. Morphologically, the new species is similar to B. lemniscatoides and B. lemniscatum (Table 1), but it differs from the former in pseudobulb shape (subglobose vs. ovoid), flower colour (purplish red vs. dark purple), sepal appendages (longitudinally crenate/undulate white plates vs. finely rugose on surface, densely papillate and not lamellate) and petals (margin entire vs. linear bidentate and serrulate near the petal base), from the latter by pseudobulbs (not tuberculate vs. strongly tuberculate), number of leaves (2 vs. 3–4), sepals (ovate-triangular, concave, 4-grooved, purplish red, outside with dense papillae and sparse purple-red hairs vs. orbicular-ovate, 3-grooved, dark purple, outside with long spreading hairs) and sepalar appendages (6–10 mm long, 0.2–0.3 mm in diam., with 6–8 flanges contorted from a light cream-purple capillary axis vs. 8–13 mm long, 0.6–1 mm in diam., 6–10 longitudinal crenate undulate plates radiate from a capillary axis).