Portulaca pilosa L., chisme. Annual, fleshy–leaved, diffuse–rooted, several—many–stemmed at base, cushionlike, with spreading principal branches and in canopy shoots upturned and often forked with each branch having a terminal inflorescence, spreading and mostly decumbent (prostrate), 3—25 cm tall; shoots typically with fleshy cauline leaves, foliage glabrous.
Stems cylindric, < 2 mm diameter, light green aging with smooth, brownish periderm, having flat, elliptic leaf scars and persistent and conspicuous axillary tufts of coarse, long white hairs.
Leaves helically alternate, simple, short–petiolate, without stipules; petiole hemicylindric, 0.8—1.3 × 0.7—0.9 mm, fleshy, whitish, at base with an abscission groove on lower side, white hairs in axil of petiole 5—7 mm long; blade linear and compressed somewhat top–to–bottom (elliptic in ×–section), < 5—10 × 1—1.5 × 0.9—1 mm, fleshy, mottled green, rounded and slightly wider at base than petiole, entire, blunt acute at tip, lacking obvious venation.
Inflorescence leafy condensed cyme, terminal, of 2—7 flowers rimmed by < 10 alternate leaves, appearing involucrelike and dish–shaped 4—5 mm across and surrounded by the radiating leaves around the rim, the inner surface of dish covered by a dense tuft of white hairs to 6 mm long, flowers sessile, bracteate, glabrous; bract + bractlets subtending flower 2 or 3, appressed to base of ovary, subequal, membranous, ± deltate, ca. 1 × 1.5 mm, persistent and scarious in fruit.
Flower bisexual, radial, when freshly open in morning in range 8—10 mm across and closing rapidly when stressed; calyx of 2 subequal and distichous “sepals” fused at base and to lower portion of ovary, outer sepal overlapping tip of shorter inner sepal, somewhat membranous, deltate, ca. 4 × 3 mm, translucent pale green, half–sheathing, not keeled, persistent and wrapped tightly around developing fruit thereby enclosing withered petals and dried filaments; petals 5, spreading, obovate, 5.5—6 × 2.5—2.7 mm, magenta but white at base, truncate to slightly notched with short point at tip; stamens 13—21 in several whorls, free; filaments 2—2.6 mm long, of the outer whorl slightly > inner stamens, magenta, with a tuft of papillate hairs at whitish base; anthers dorsifixed, dithecal, 0.6—0.7 mm long, bright yellow, the sacs unequal, the longer chambers touching at tip, longitudinally dehiscent; pollen bright yellow; pistil 1; ovary half–inferior, ovoid, exposed portion conic, 1 mm long, lime green, glabrous, 1–chambered with many ovules attached on vertical funiculi to a basal post; style 3 mm long, 4—6–branched at 2 mm from base, white at base to rose or magenta and hollow at fork, the branches ascending to spreading at same level as anthers, strap–shaped, ca. 1—1.2 mm long, magenta, magenta papillate–ciliate.
Fruit capsule (pyxis), with dehiscence around circumference (circumscissile) 1/3 from base, ca. 40–seeded, ovoid rounded on top, 2.1—2.4 × 1.6 mm, tan, seeds attached via conspicuous, vertical funiculi to central, basal placentae; basal portion cup–shaped and persistent among long white hairs on involucre; dried perianth twisted and adherent to exposed fruit, withered like a peaked cap.
Seed compressed snail–like with curved embryo, 0.4 × 0.4 × 0.3 mm, ± glossy black, finely warty (tuberculate), the bulging cells in rows around curved seed.
A. C. Gibson