Rivina humilis
Content
Description
Annual herb or subshrub to 1.2 m tall, often shrubby and with spreading, vinelike branches from base. Stem ribbed, glabrous to pubescent. Leaves lanceolate, ovate-lanceolate, ovate or oblong, sometimes elliptical, to 15 x 9 cm, entire or with low teeth, acute or acuminate at apex, rounded to truncate at base, glabrous or pubescent, often undulate; petiole to 11 cm long, canaliculate, pubescent with stiff hairs continuing on midvein of lower leaf surface. Inflorescence an axillary or terminal raceme to 20 cm long, axes glabrous or pubescent; bracts very narrowly lance-linear, 0.6-1 mm long, membranous, ciliate especially at mid-margin; bracteoles scalelike, immediately subtending perianth,<0.3 mm long; pedicels glabrous, 2.4-4 mm long in flower, elongating to ca. 7 mm in fruit. Tepals 4, obovate to linear-oblong or oblong-elliptic, 2.0-3.5 x 1 mm, obtuse, glabrous or ciliate, white, greenish or pinkish, partially enclosing fruit; stamens 4, ca. 1.3-1.5 mm long, anthers 0.5-1 mm; ovary ca. 1 mm, style 0.5 mm. Fruit ovoid, 2.5-4.5(-5) mm wide, smooth, red (sometimes orange or purple), black when dry; seed 2.5-3.5 mm, bluish-black, glabrous or hispid.
Distribution
Argentina present, Guianas present, New World present, Pantropical present, Southern America, Southern United States present
New World from southern United States and West Indies to Argentina, now a pantropical weed, in the Guianas a weed in disturbed areas; 11 collections studied (GU: 2; SU: 7; FG: 2).