10. Waltheria Linnaeus, Sp. Pl. 2: 673. 1753; Gen. Pl. ed. 5. 304. 1754.
[For Augustin Friedrich Walther, 1688–1746, German physician, anatomist, and botanist at Leipzig University] [For Augustin Friedrich Walther, 1688–1746, German physician, anatomist, and botanist at Leipzig University]
Janice G. Saunders
Subshrubs [herbs, shrubs], prostrate to erect, taprooted. Stems unarmed, hairy, hairs stellate and/or simple, sometimes also glandular. Leaves petiolate; stipules deciduous, narrowly triangular or linear-triangular; blade: margins dentate, serrate, or crenate. Inflorescences axillary, cincinni in double or compound dichasial clusters, glomerulate, or paniculiform, 5–40-flowered; epicalyx absent; bracts 4, unilateral subtending floral pair, unequal or subequal. Flowers sweet-smelling, sessile or subsessile, homostylous [mostly distylous]; sepals connate 1/2–2/3 length, nectary present; petals late-deciduous, pale yellow, bright yellow, or yellow-orange, usually darker in corolla throat, spatulate, clawed [rarely not clawed], lamina obovate, oblong, oblanceolate, or obtriangular; androgynophore absent or present, to 0.7 mm; stamens connate most of length [connate basally to entirely]; anthers 2-thecate, oblong or ovate; staminodes 0; ovary 1-locular, obovoid or obconic, stipitate or not; ovules 2 per locule; styles included, cylindric; stigmas 10–40-branched, apex slightly exserted above stamen apices and corolla. Fruits capsules, 1-locular, obconic, obovoid, or oblique, apically hairy, dehiscence partially or completely loculicidal. Seeds 1(or 2) per locule, brown or black, slightly laterally compressed, obovoid, obconic, or oblique, smooth or minutely granulate; endosperm present; cotyledons oblate [widely elliptic to elliptic, circular]. x = 5, 6, 7, 10, 13.
Species ca. 60 (3 in the flora): sw, se United States, Mexico, West Indies, Bermuda, Central America, South America, Asia, Africa, Atlantic Islands, Indian Ocean Islands, Pacific Islands, Australia; tropical and subtropical areas.
Waltheria albicans Turczaninow and W. rotundifolia Schrank are found in Mexico, and apparent hybrids of them with W. indica in the broad sense occur in the United States.
SELECTED REFERENCES Köhler, E. 1971. Zur Pollenmorphologie der Gattung Waltheria L. (Sterculiaceae). Feddes Repert. 82: 125–153. Köhler, E. 1976. Pollen dimorphism and heterostyly in the genus Waltheria L. (Sterculiaceae). In: I. K. Ferguson and I. Muller, eds. The Evolutionary Significance of the Exine. London. Pp. 147–161. Saunders, J. G. 1995. Systematics and Evolution of Waltheria (Sterculiaceae). Ph.D. dissertation. University of Texas.