刺花莲子草 ci hua lian zi cao

Achyranthes repens Linnaeus; Alternanthera repens (Linnaeus) Link.

Herbs annual. Stem diffuse, creeping, much branched, 20-30 cm tall, densely rigidly hairy. Petiole 3-10 mm, glabrous or hairy; leaf blade ovate, obovate, or elliptic-obovate, 1.5-4.5 × 0.5-1.5 cm, unequal in each pair, glabrous or annexed pilose, base acuminate, apex obtuse. Heads sessile, 1-3, axillary, white, globose or oblong, 5-10 mm. Bracts lanceolate, ca. 4 mm, spiny at apex; bracteoles lanceolate, 3-4 mm, apex acuminate, without spines. Tepals unequal, outer 2 lanceolate, ca. 5 mm, 3-veined below, rigid after anthesis, midvein stretching into spines; central segment elliptic, 3-3.5 mm, compressed; inner 2 small, enclosing ovary. Stamens 5; filaments 0.5-0.8 mm; pseudostaminodes shorter than filaments, entire or irregularly dentate. Style very short. Utricles brown, broadly ellipsoid, 1-1.5 mm. Fl. May, fr. Jul.

Roadsides. Fujian, Sichuan [native to South America; naturalized in Bhutan, Myanmar, Thailand, ?other parts of Indo-China, Australia, and United States].

One of us (Clemants) notes that the name Alternanthera pungens has been misapplied here and that this taxon should instead be treated as A. caracasana Humboldt et al.