Orchid Information - Family Orchidaceae Subfamily Epidendroideae Tribe Arethuseae

Arethuseae Lindl., Coll. Bot. App. (1826). Type genus: Arethusa L.

Synonyms:

• Glomereae Pfitzer, Entw. Nat. Anordn. Orch. (1887) 101 (as 'Glomerinae'). Type genus: Glomera Blume.

Epiphytes, lithophytes, or rarely terrestrials, herbaceous. Rhizomes often well developed. Roots with velamen. Stems reed-like, pseudobulbs or rarely a corm, when young enveloped in cataphylls. Leaves 1 to many, distichous, conduplicate or more often convolute, deciduous, often plicate; leaf sheath tubular, absent when the leaf is situated on top of a pseudobulb; petiole often present. Inflorescence a raceme, rarely a panicle, sometimes reduced to a single flower, terminal, proteranthous, synanthous, or hysteranthous, or seemingly lateral but actually heteranthous on reduced shoots that do not develop into normal pseudobulbs and leaves, usually few- to many-flowered; peduncle a single internode; floral bracts caducous or persistent, ovate to linear, acute to acuminate. Flowers resupinate or not. Median sepal usually free or all three sepals connate (Glomera). Lateral sepals similar to the median sepal but often oblique, rarely connate to each-other, often keeled; mentum not present. Petals free or not, lanceolate, ovate, obovate to oblanceolate, hardly spreading to strongly reflexed. Lip usually immobile on the base of the column, sometimes hinged and mobile, adnate to column, entire or 3-lobed, the lobes entire to crenate; hypochile often distinct, concave or saccate, sometimes with a spur; epichile flat or convex; coloured trichomes, papillae or plate-like keels often present, wart-like calli mainly in Coelogyne; base of lip with nectar. Column often apically dilated and winged to hood-like, sometimes with lateral arms; column foot absent or present; anther helmet-shaped, 2-locular; pollinia 4 or 8, usually pear-shaped, soft, waxy, with thick, granular, coherent or connate or membranous caudicles; viscidium absent or indistinct, semi­liquid; stigma often cup-shaped with raised margins, its upper margin forming a rostellum. Ovary glabrous or with indument. Fruit a capsule, ellipsoid to subglobose, sometimes winged, often opening with 3 valves and 3 jugae.
( after Cribb 2005)

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