Cycnium

Annual or perennial herbs, hemiparasitic on roots, turning dark on drying; stems erect to procumbent, simple to much branched; rhizomes tuberous or elongated, sometimes woody. Leaves opposite or subopposite, sometimes alternate or in whorls of 3, sessile or shortly petiolate, linear to ovate, entire or variously dentate. Flowers often large, axillary or supra-axillary, or in terminal spikes or racemes, pedicellate to sessile, bracteate and usually bibracteolate. Bracts leaf-like; bracteoles, when present, usually adnate to base of calyx, rarely arising on pedicel or above base of calyx. Calyx tubular, cylindrical or campanulate, rarely urceolate, (4)5-lobed, 10(11)-veined or -ribbed; tube straight; lobes equal or subequal, deltoid-ovate, lanceolate or linear, usually shorter than tube, rarely longer. Corolla bilabiate, 5-lobed, large, salverform, exserted, not persisting around fruit; tube slender, elongated, subcylindrical or sometimes gradually widening above, straight or gently curving near apex, usually with throat bearded; limb spreading; upper lip 2-lobed with lobes connate higher up than rest, interior in bud; lower lip 3-lobed, lobes shorter than tube, obovate. Stamens 4, didynamous, arising +/- in middle of corolla tube, sometimes below, but pairs at 2 levels, included; filaments linear, unilaterally bearded; anthers unithecate, erect, dorsifixed; staminodes 0. Ovary bilocular, ovate or ovoid, +/- compressed, glabrous; ovules many; style terete, straight, included, not exceeding lower pair of stamens, base persistent; stigma simple, terete or compressed, linear-lanceolate, slightly thickened, +/- same length as style, sometimes 2-lobed. Fruit usually an ovoid, oblong or globose capsule, acute, apiculate or sometimes obliquely beaked and/or winged along 1 or both sutures, loculicidal along apical parts of both sutures or rarely dehiscing along upper-distal suture only, or fruit a globose to ovoid, indehiscent berry. Seeds small, ovoid or oblong; testa reticulate or reticulate-tuberculate, rarely almost smooth, firmly connected with lower cell layers. x = 12, 19 (1 report each, aneuploids, polyploidy).