Alternanthera caracasana

Herbs, perennial, 1-5 dm. Stems prostrate to procumbent, villous, glabrate. Leaves sessile; blade rhombic-ovate, oval, or obovate, usually longer than broad, 0.5-2.5 × 0.3-1.5 cm, apex rounded, apiculate, sparsely villous, glabrate. Inflorescences axillary, sessile; heads white to stramineous, ovoid, 0.5-0.8 × 0.4-0.6 cm; bracts shorter than tepals, apex long-attenuate, aristate. Flowers: tepals dimorphic, whitish to stramineous, lanceolate, 3-5 mm, apex acuminate, spinose tipped, densely villous, hairs barbed; stamens 5; pseudostaminodes triangular or subulate, shorter than filaments, margins usually entire, rarely dentate. Utricles included within tepals, brown, ovoid-orbicular, 1.5 mm, apex slightly truncate. Seeds ovate-orbiculate, 1-1.5 mm.

Flowering summer-fall. Gravel, sand bars, sidewalks; 0-2000 m; introduced; Ala., Ariz., Ark., Calif., Fla., Ga., La., Md., Miss., N.Mex., N.C., Okla., S.C., Tex.; Mexico; Central America; South America.

FNA 2003, Hunn 2008, Quattrocchi 2000

Duration: Perennial Nativity: Non-Native Lifeform: Forb/Herb General: Herbaceous perennials, ; stems prostrate to procumbent, villous, glabrate, 1-5 dm long. Leaves: Sessile; blade rhombic-ovate, oval, or obovate, usually longer than broad, 0.5-2.5 0.3-1.5 cm, apex rounded, apiculate, sparsely villous, glabrate. Flowers: Inflorescences axillary, sessile; heads white to stramineous, ovoid, 0.5-0.8 0.4-0.6 cm; bracts shorter than tepals, apex long-attenuate, aristate; tepals dimorphic, whitish to stramineous, lanceolate, 3-5 mm, apex acuminate, spinose tipped, densely villous, hairs barbed; stamens 5; pseudostaminodes triangular or subulate, shorter than filaments, margins usually entire, rarely dentate; flowering summer-fall. Fruits: Utricles included within tepals, brown, ovoid-orbicular, 1.5 mm, apex slightly truncate. Seeds ovate-orbiculate, 1-1.5 mm. Ecology: Gravel, sand bars, sidewalks, disturbed areas; 0-6562 ft (0-2000 m). Distribution: Introduced to southern n America: CA east to MD and south to FL Notes: Can be distinguished by its prostrate habit, hairy stems, dark green leaves and sessile, axillary spikes <1cm wide with clusters of small flowers with white tepals. Distinguished from Guilleminea by possessing spikes instead of round, dense clusters (glomerules), Gomphrena by possessing axillary sessile spikes instead of peduncled round clusters and from Alternanthera pungens by having densely hairy tepals that are 3-5mm. This introduced herb is naturalized in many regions and can be noxious in others. Ethnobotany: Used by the Chinchero of Peru as a tea during childbirth, and by Zapotec in southern Mexico for diarrhea and to treat -fright- Etymology: Alternanthera is derived from the latin alternus, -to alternate- and anthera is from -anther-, referring to the alternate anthers in most species being barren. Caracasana comes from the Caracas region of Venezuela, where it is native. Synonyms: Alternanthera peploides, Achyranthes peploides Editor: FSCoburn 2014