Source:
SSA
Description:
Annual or perennial herbs; stems simple or branched, erect, sometimes creeping or diffuse, often juicy, translucent and turgescent, without stinging hairs; plants monoecious or dioecious by abortion. Leaves opposite, pairs equal or very unequal, entire or dentate, petiolate, with linear cystoliths; stipules intrapetiolar, completely connate. Inflorescences axillary cymes, either dense and head-like or lax and paniculately branched, or flowers solitary; bracts small, rarely few and larger, deltate to linear. Flowers unisexual, male and female flowers in same cyme. Male flowers: tepals (2-)4, concave, subvalvate, sometimes connate into a truncate cup, often mucronate or appendaged on back; stamens as many as tepals; rudimentary ovary conical or oblong. Female flowers: tepals 3, equal, or sometimes 1 tepal enlarged and gibbous or hood-like; staminodes 3, opposite tepals, scale-like, minute or inconspicuous, under tension and ejecting mature achene; ovary straight; stigma sessile, composed of a dense tuft of short hairs, deciduous. Achene sessile, laterally compressed, slightly oblique, ovate to orbicular, +/- smooth, free from perianth at maturity, not or only partly enclosed by hood-like tepal. Seed with thin coat; embryo with large cotyledons. x= 10, 12, 13 (polyploidy).
Distribution:
Species +/- 250, almost pantropical in distribution and in most subtropical regions with exception of Australia and New Zealand; 2 in sthn Afr.: Pilea rivularis Wedd. indigenous in the Northern Province and *P. microphylla (L.) Liebm., a species with very small, 1-8 mm long, entire leaves, a native of tropical America, is cultivated as an ornamental garden plant or occurs as a garden weed, e.g. in KwaZulu-Natal.
Classification:
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