2. Portulaca oleracea L. (common purslane, pusley, pursley)

P. oleracea ssp. granulato-stellulata (Poelln.) Danin & H.G. Baker

P. oleracea ssp. nicaraguensis Danin & H.G. Baker

P. oleracea ssp. nitida Danin & H.G. Baker

P. neglecta Mack. & Bush

P. retusa Engelm.

Pl. 507 i–k; Map 2314

Plants with the lateral roots fibrous. Stems 5–50 cm long, prostrate or occasionally ascending, glabrous. Leaf blades 4–30(–50) mm long, 2–15 mm wide, flattened, spatulate to obovate, oblanceolate, or oblong-oblanceolate. Stipules absent (stem nodes glabrous). Inflorescences glabrous or rarely with sparse, inconspicuous, short hairs. Sepals 2.5–4.0 mm long (measured to the base of the ovary). Petals 3–5 mm long, light yellow to yellow. Stamens 6–12(–18). Fruits 5–9 mm long, 4–8 mm wide. Seeds 0.6–1.0 mm long, variously orbicular to more or less kidney-shaped, the surface smooth or more commonly appearing roughened or with minute, blunt tubercles, dark brown to black, not iridescent. 2n=18, 36, 54. June–November.

Scattered to common nearly throughout the state (nearly worldwide). Banks of streams and rivers, margins of ponds, lakes, and marshes, seeps, bases, ledges and tops of bluffs, upland prairies, and glades; also crop fields, fallow fields, ditches, gardens, lawns, sidewalks, railroads, roadsides, and open disturbed areas.

Some North American authors have considered this species as possibly introduced from the Old World, but Matthews et al. (1993) summarized several sources of data that suggest a native presence in the Americas, including observations of plants growing in some states by the earliest plant explorers and the presence of seeds at archaeological sites and in sediment cores that predate the colonization of North America by Europeans. The species is considered among the worst agricultural weeds in the world and can become an aggressive pest in gardens. Moerman (1998) noted that various tribes of Native Americans ate plants raw and cooked as a vegetable and that the species also was used medicinally to treat worms, ear aches, bruises, and burns. In the Old World, some races of P. oleracea have been cultivated traditionally as fodder and vegetable crops in the Middle-East.

Opinions have varied greatly on the taxonomy of the P. oleracea complex, which is treated here in a broad sense. Portulaca neglecta and P. retusa are among the segregates that were reported from Missouri (Steyermark, 1963); the former was characterized as having ascending stems, relatively long leaves, and relatively numerous stamens compared to typical P. oleracea, whereas the latter was said to differ in its more rounded petals, slightly notched leaf tips, and more sharply pointed tubercles on the seed coat. In his taxonomic account of the species of Portulaca in the Americas, Legrand (1962) placed both of these names in synonymy under P. oleracea based on his observations that the descriptions and specimens he had examined fell within the overall range of variation in the species. Matthews and Levins (1985b) and Matthews et al. (1993) studied the P. oleracea complex in temperate North America and reached a similar conclusion, noting that this nearly cosmopolitan species reproduces mostly through self-pollination, which favors the maintenance of local races differing slightly but consistently in morphology. Danin et al. (1978) attempted to correlate ploidy and seed morphology and recognized nine subspecies of P. oleracea, of which ssp. granulato-stellulata, ssp. nicaraguensis, ssp. nitida, and ssp. oleracea were mapped as occurring in Missouri. None of the other named species-level variants was synonymized with these subspecies and in practice the minor differences in seed-coat morphology said to characterize these taxa do not serve to separate Missouri plants adequately (Matthews et al., 1993).