Description

Key Characters:

Growth Form: Annual or perennial herbs, rarely shrubs, subshrubs, or lianas.

Stems:

Roots:

Leaves: Leaves simple. Alternate. Base attenuate to cordate or auriculate. Margins flat, undulate, or crisped. Petiolate. Stipules present, ocreae membranous or dry and membranous, often brownish, thin, brittle, the margins becoming lacerate.

Flowers: Flowers in axillary glomerules, these contiguous or well–separated, arranged in terminal, racemose or paniculate inflorescences, each flower on a pedicel jointed to the short peduncle. Flowers bisexual (perfect) or unisexual (and then plants dioecious or monoecious), actinomorphic. Tepals 6, connate at base into a minute floral tube, outer 3 much smaller than inner ones, usually lanceolate or subulate, at least somewhat spreading, not especially enlarging in fruit, inner 3 (valves) erect, usually developing wings with entire, toothed, or spiny margins and often 1 or all developing a grain-like tubercle, greatly enlarging in fruit, loosely coherent to the nut. Stamens 4–6; filaments distinct, free, glabrous; anthers yellowish to reddish, elliptic to ovate. Ovary superior, (2)3(4)-carpellate, 1-celled; ovule 1; styles 3; stigmas fimbriate, dry.

Fruit: Trigonous nuts; enclosed by the burr-like tepals.

Ploidy:

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