167. Arachnis Blume, Bijdr. 365. 1825.
蜘蛛兰属 zhi zhu lan shu
Authors: Xinqi Chen & Jeffrey J. Wood
Arachnanthe Blume; Arhynchium Lindley & Paxton.
Herbs, epiphytic, robust, monopodial. Stems scrambling, elongate, often to several meters, branched, leafy. Leaves oblong, rigid, somewhat fleshy or leathery, base sheathing, apex bilobed. Inflorescence lateral, ascending or pendulous, rigid, often long and branched, few to many flowered; peduncle and rachis slender. Flowers fragrant, resupinate, often large and showy, usually widely opening, often spiderlike. Sepals and petals similar, spreading, narrowly oblong to linear, usually widened toward apex; lateral sepals and petals often falcate-curved. Lip short, 3-lobed, jointed to column foot by a short movable strap, base saccate or spurred; mid-lobe with a raised, central ridge or callus; column short, stout; stipe short, broad; viscidium broadly ovate; pollinia 4, appearing as 2 unequal masses, waxy.
About 13 species: from NE India and mainland Asia to Indonesia, New Guinea, and the Pacific islands; one species in China.