Weeds as a source for human consumption. A comparison between tropical andtemperate Latin America

Weeds abound in urban and agricultural environments. Depending on region an d site, up to 66% of weed species are edible, and may constitute an additio nal food source for humans. Based on 400 samples, 1/4m(2) each, collected i n tropical areas (e.g., roadsides, urban vacant lots, streets, sugar cane a nd coffee plantations in Coatepec, Mexico), average figures of edible fresh biomass vary between 1277 and 3582 kg/ha. A similar survey performed in a temperate area (739 samples in Bariloche, Argentina) showed mean values bet ween 287 and 2939 kg/ha. A total of 43 species were sampled in Coatepec and 32 species in Bariloche. The general means were 2.1 and 1.3 tons/ha, respe ctively. At a greater geographic scale, a comparison between Mexican and Ar gentine weeds shows that, proportionately, the food parts vary a little bet ween regions. In general, from higher to lower, the order of uses goes from leaves, seeds, roots, fruits, herbals, flowers and condiments. Edible root s (including bulbs and rhizomes) appear to be more common among perennials than among annuals.