Arachnis Blume
Habit: epiphytic herbs
Stem: branched, unbranched, with leaves
Leaf: characteristics: sheathing or noding at base, margin recurved or apex lobed, base clasping
Leaf: position: distichous
Inflorescence: type: raceme, panicle
Inflorescence: position: laterally on stem
Inflorescence: other characteristics: branched, unbranched
Flower: other characteristics: spreading
Sepal: lateral sepals dilated or saccate at base or bent downward
Petal: similar to sepals
Labellum: with sac or spur or auricles at base, 3-lobed, with longitudinal ridges or keels
Column: with column foot
Pollinia: number: 4
Pollinia: other characteristics: with caudicle or viscidium, with stipe
Stipe: shape: triangular or subtriangular
Viscidium: other characteristics: wider than stipe, as wide as stipe