Description

Key Characters:

Growth Form: Non-aromatic perennial vines or rarely erect perennial herbs, sometimes woody near base.

Stems: Stems scandent or decumbent, quadrangular or terete (cylindrical), many-branched, often pubescent.

Roots:

Leaves: Leaves simple. Opposite. Blades occasionally deeply lobed and approaching palmately compound on young plants. Surfaces glabrous or variously pubescent, Blades membranous, smooth to rugose. Petiolate or sessile. Stipules absent.

Flowers: Flowers 1–24 per verticillaster, on short pedicels, these rarely on a common peduncle, axillary, the flowering axils occasionally more frequent near shoot apex, or located on axillary shoots. Calyx radially symmetrical or bilaterally symmetrical through various degrees of connation of lobes, when bilaterally symmetrical, upper lip 3-lobed, lower lip 2-lobed, calyx tubular or campanulate, enlarging in fruit, increasing only in width, splitting longitudinally, usually persistent or sometimes only ventral 1/2 persistent. Corolla bilabiate, white, pink, red, purple, very dark maroon, cream, yellow, or green, occasionally yellow or green and tinged brown, tube narrowly funnelform, falcate or straight, upper lip entire or 2-lobed, flat or concave, lower lip nearly always shorter, 3-lobed, the lobes flat or margins revolute, ovate, of similar size, distal portion of corolla sparsely to densely pubescent externally, the hairs simple or multicellular, occasionally glandular pubescent within, otherwise glabrous; nectary disk often present at base of ovary, annular or developed on anterior side only. Stamens 4, both pairs of similar length or upper pair slightly longer, included within corolla or well–exserted beyond upper lip; filaments inserted near throat, pubescent; anthers dithecal; anther sacs divaricate, opening by longitudinal slits. Ovary superior, 2-carpellate, each carpel longitudinally divided, placentation basal-axile; ovules 1 per ovary lobe; style 1, exserted, arising between lobes, usually cleft, diverging after anther dehiscence, shortly 2-lobed, the lobes subulate; stigmas 2.

Fruit: Nutlets 1-seeded; drupaceous; black at maturity; margins slightly winged; obliquely attached at base; included within calyx at maturity; exocarp fleshy; obovoid. Seeds with endosperm absent or scanty and oily.

Ploidy:

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