3. Portulaca pilosa L.

P. mundula I.M. Johnst.

P. parvula A. Gray

Pl. 507 f–h; Map 2315

Plants with the taproot and main lateral roots often somewhat thickened and fleshy. Stems 8–35 cm long, prostrate to strongly ascending, often sparsely pubescent, more densely so near the tip. Leaf blades 5–20 mm long, 1–3 mm wide, not flattened (circular to semicircular in cross-section), linear to narrowly oblong-lanceolate. Stipules represented by dense, conspicuous tufts of long, somewhat contorted hairs in the leaf axils. Inflorescences with dense, conspicuous tufts of long, somewhat contorted hairs. Sepals 3–7 mm long (measured to the base of the ovary). Petals 4–8 mm long, red to reddish purple. Stamens 10–15 (to numerous). Fruits 3.5–7.0 mm long, 2.0–4.5 mm wide. Seeds 0.4–0.6 mm long, variously orbicular to kidney-shaped, the surface pebbled or with minute, blunt, irregular tubercles, dark gray to black, not iridescent. 2n=8, 16. May–October.

Scattered in the southwestern portion of the state north to Jackson County; uncommon and sporadic farther east (southern U.S. north to Arizona, Kansas, and North Carolina; Mexico, Central America, South America, Caribbean Islands). Glades, sand prairies, and ledges and tops of bluffs; also railroads, roadsdies, and open disturbed areas.

Many early botanists recognized three or more species within the P. pilosa polyploid complex (Steyermark, 1963). Portulaca mundula was described to account for plants with relatively large flowers and reddish purple corollas (this includes the plants growing in Missouri). True P. pilosa was said to have slightly smaller flowers with reddish purple corollas. Plants with relatively small flowers and yellow to orangish or bronze-colored corollas were described as P. parvula. Matthews and Levins (1985a, b) and Matthews et al. (1992) showed that there is almost complete overlap in flower sizes as well as for most other quantitative characters of these plants across their relatively large geographic range and that yellow- and red-flowered variants can grow in the same population. Matthews et al. (1992) also suggested that P. pilosa is a tetraploid (2n=16) in Mexico and portions of the southeastern United States and a diploid (2n=8) in much of the remainder of the North American portion of its range, with no measurable correlation between ploidy and any morphological features.