Plants annual; roots fibrous. Stems prostrate to suberect, often pinkish, succulent; trichomes conspicuous at nodes and in inflorescence; branches to 3-20(-25) cm. Leaf blades linear to oblong-linear, terete to hemis-pheric, 2-14(-20) × 0.4-2(-3) mm, apex obtuse to acute; involucrelike leaves 4-8. Flowers 3-8 mm diam.; petals yellow, obovate, 2-4 × 1-2.5 mm; stamens 4-18; stigmas 3-4(-5). Capsules ovoid, 1.1-2 mm diam. Seeds gray or leaden, 0.3-0.5(-0.6) mm diam.; lateral surfaces with densely arranged, flattened, stellate cells, tubercles absent; usually with a smooth, occasionally papillose, spine abaxially. 2n = 18. Flowering late spring-early fall. Dry soil, sand dunes, arroyos; 900-2300 m; Ariz., Calif., Colo., Nev., N.Mex., Okla., Tex., Utah; West Indies; Central America; South America. Young plants of Portulaca halimoides in desert areas may exhibit reddish stems and sepals. As the yellow petals fade, the persistent, reddish sepals cover the top of the capsule, giving the false impression of red flowers. Immature seeds are reddish brown to brownish black and may be papillose. Morphologic variability occurs in relation to habitat differences over the range of this species. Desert conditions produce depauperate plants; more robust specimens occur in Central America and South America. The type of P. halimoides is conspecific with P. parvula A. Gray within this context. A. Gray (1887) cited P. halimoides from the Florida Keys; that is unconfirmed and is likely a confusion with P. rubricaulis.

PLANT: Annual herbs from a slender, fibrous root. STEMS: much branched, prostrate to somewhat ascending, 2-16 cm long, often reddish, glabrous. LEAVES: alternate, linear, cylindrical or nearly so, 4-15 (18) mm long, 0.5-3 mm wide; nodes with conspicuous white-villous hairs. INFLORESCENCE: white-villous; involucral bracts 6-8, 3-8 mm long, 0.5-3 mm wide. FLOWERS: solitary or clustered at the ends of branches; sepals typically turning reddish at maturity; petals 2-2.5 mm long, yellow to copper colored; stigmatic branches 3-4. CAPSULE: 1-2 mm in diameter; stipe 1-1.5 mm long. SEEDS: iridescent grayish or blackish at maturity, rounded or stellate-tuberculate. NOTES: Sandy or gravelly soils, in open or brushy sites, often in disturbed places: Cochise, Coconino, Graham, Greenlee, Maricopa, Mohave, Navajo, Pima, Pinal, Santa Cruz, Yavapai, Yuma cos.; 350-2050 m (1100-6800 ft); Mar–Nov; MO to CO; s to TX and NM. REFERENCES: Allison Bair, Marissa Howe, Daniela Roth, Robin Taylor, Tina Ayers, and Robert W. Kiger., 2006, Vascular Plants of Arizona: Portulacaceae. CANOTIA 2(1): 1-22.