Sp. Pl. 2: 673. 1753.
Plants branched or nearly simple, to 7–12 dm, indument variable, tomentose to short-woolly, sparsely to densely pubescent. Stems to 8 mm wide, nodes even or extended to 0.5 mm. Leaves: stipules linear-triangular, 3–6 mm; petiole 2.5–5 cm × 1–4 mm; blade concolor or discolor, drying olive, ovate-oblong to lanceolate, to 7(–10) × 5 cm, base subcordate to obtuse, margins crenate-serrate, serrate, irregularly serrate, or crenate-dentate, apex narrowly rounded, obtuse, or subacute, surfaces tomentose or pubescent, trichome rays 0.4–1 mm, and sparsely hispidulous, slightly scabrous or not. Inflorescences subsessile, or on short pedunclelike lateral branches to 3.6 cm, glomerules 5–20 along stems, compact, often dense, sympodial, at times lax clusters with terminal flower and subtending dichasia; bracteoles free or with 1 adherent to stipule forming an elliptic 2-cuspidate foliole at glomerule base, bracts subequal, lanceolate or linear, 0.3–1.5 mm wide, apex acute, entire. Flowers sessile or subsessile; calyx 4.2–setose apically; styles 0.9–1.7 × 0.1–0.3 mm, lateral or excentric, broader and stellate-hirsute distal to base; stigmas 12-branched, plumose (1.2–1.4 × 0.5–0.8 mm, column 0.9–1.2 mm, branches to 0.7 mm) or dissolute-penicillate (0.6–1.2 × 0.7–1.6 mm, column 0.4–0.7 mm, branches to 1.1 mm). Capsules oblique, obconic, or obovoid, 2.1–3 × 1.5–2 mm, walls with endocarp corneous for 1+ mm from apex, sometimes merely membranous along one or both valve margins laterally; partially apically dehiscent to 2-valvate. Seeds dark brown, obovoid or obconic, 2–2.2 × 1.2–1.5 × 1–1.3 mm, smooth. 2n = 24, 26 (India), 40 (Africa).
Phenology: Flowering and fruiting year-round.
Habitat: Ruderal communities, disturbed scrublands, scrub hummocks, pine-oak sandhills, dunes, open savannas, dry coastal hummocks, sandy or shell soil
Elevation: 0–1000 m
Ala., Ariz., Fla., Tex., Mexico, West Indies, Bermuda, Central America, South America, Asia, Africa, Atlantic Islands, Indian Ocean Islands, Pacific Islands, Australia.
Robert Brown (in J. H. Tuckey 1818) was the first to unequivocally synonymize the names Waltheria americana and W. indica published by Linnaeus in the same work. Brown adopted the name W. indica for the combined species and thus gave priority to that name.
Waltheria indica in the narrow sense is globally in need of revision, being very complex and problematic. Heterostyly has been reported for some populations of W. indica in India (B. Bahadur et al. 1996). Flora area populations have the pistil subequal (0.2–0.5 mm longer) and more or less homostylous, or up to 1 mm longer than stamens, more like monomorphic pin floral morphology. Multiple introductions are apparent from the variability seen within the flora area. Apparent hybrids of W. indica with other species are found in Arizona, Florida, and Texas.