Polystachya Hook.

Orchidaceae, V. S. Summerhayes. Flora of Tropical East Africa. 1968

Morphology General Habit

Small, medium-sized or rarely large epiphytic or less commonly lithophytic or terrestrial herbs

Morphology Stem

Stems often pseudobulbous, caespitose or less commonly spaced on a creeping rhizome, sometimes branched or superposed, 1–several-noded, 1–several-leaved

Morphology Leaves

Leaves suberect to spreading, thin-textured, coriaceous or rarely fleshy, often distichous, linear or lanceolate to oblong-elliptic or oblanceolate, emarginate, acute, obtuse or acuminate at the apex

Morphology Reproductive morphology Inflorescences

Inflorescence terminal, erect to pendulous, 1–many-flowered, simple or branching; branches sometimes secund; bracts suberect to reflexed, setose or lanceolate to ovate or obovate, acute or acuminate to mucronate

Morphology Reproductive morphology Flowers

Flowers minute to fairly large, mostly with lip uppermost, non-resupinate, mostly rather drably coloured, ± fragrant, often pubescent

Morphology Reproductive morphology Flowers Calyx

Dorsal sepal mostly porrect, lanceolate to ovate-elliptic; lateral sepals ± oblique, attached to the column-foot to form a more or less prominent mentum

Morphology Reproductive morphology Flowers Corolla

Petals linear to obovate

Morphology Reproductive morphology Flowers Labellum

Lip entire to 3-lobed, with or without a basal callus, glabrous, pubescent or farinose, often recurved and difficult to flatten

Morphology Reproductive morphology Flowers Column

Column porrect, mostly short and stout, with a ± elongate foot; pollinia 2, ovoid; stipe 1, square or subtriangular to oblong or linear; viscidium small to large, circular or elliptic; rostellum mostly obscure, bifid in front, rarely slightly elongate and beak-like.

George R. Proctor (2012). Flora of the Cayman Isands (Second Edition). Royal Botanic Gardens, Kew

Morphology General Habit

Epiphytic, lithophytic or terrestrial herbs with slender or pseudobulbous stems clustered or distant along the rhizome, 1–several-leaved

Morphology Leaves

Leaves conduplicate, coriaceous, thin or fleshy

Morphology Reproductive morphology Inflorescences

Inflorescences terminal, peduncle enclosed by scarious sheaths, racemose or paniculate with more or less secund branches, few- to many-flowered

Morphology Reproductive morphology Flowers

Flowers generally small, mostly non-resupinate; sepals free; lateral sepals attached to the column foot forming a mentum; petals smaller than the sepals, free; lip simple or trilobed, attached to and articulate with the column foot, forming part of the mentum, disc usually callose and pubescent

Morphology Reproductive morphology Flowers Column

Column short, semiterete, foot distinct. Anther terminal, operculate, incumbent, pollinia 4, globose or ellipsoidal, hard, waxy, attached to a single short stipe and an ovate to elliptic viscidium

Morphology Reproductive morphology Flowers Gynoecium Stigma

Stigmas confluent, transverse under the rostellum

Morphology Reproductive morphology Fruits

Capsules ellipsoid to cylindrical.

Distribution

A pantropical genus of about 150 species, particularly species rich in Africa.

Orchidaceae, V. S. Summerhayes. Flora of Tropical East Africa. 1968

Morphology General Habit

Terrestrial or lithophytic herb with clustered leafy stems

Morphology Leaves

Leaves grass-like, articulated below to a sheathing base

Morphology Reproductive morphology Flowers

Flowers numerous in dense terminal racemes, showy, with a strong sweet scent

Morphology Reproductive morphology Flowers Calyx

Sepals subequal, ± spreading, the laterals slightly united at the base and slightly adnate to the base of the lip

Morphology Reproductive morphology Flowers Corolla

Petals free, similar to the sepals

Morphology Reproductive morphology Flowers Labellum

Lip somewhat spreading, sessile at the base of the column and ± adnate and parallel to it, entire, fleshy, devoid of keel or crests, but the basal and central part distinctly to slightly hairy

Morphology Reproductive morphology Flowers Column

Column short and thick, rounded at the back, excavated in front, with sparse short bristles on the angular edges; column-foot obscure, forming an obscure mentum with the lateral sepals; anther galeate, subhemispherical, obtusely umbonate at the apex, the basal margins retuse; pollinia attached to a semicircular viscidium, in 2 pairs of 2, each consisting of a smaller discoid one fitting against a larger concavo-convex one, separated by thin folds of tissue when young which later roll up forming ridges inside the anther- cap.