Flora of the Hawaiian Islands
Literature for Bidens micrantha
Wagner et al., 1990, 1999. Literature for Bidens micrantha subsp. ctenophylla
Wagner et al., 1990, 1999. Literature for Bidens micrantha subsp. kalealaha
Wagner et al., 1990, 1999.
   Asteraceae -- The Sunflower Family Bibliography
      Bidens micrantha
General Information
Erect, suffrutescent perennial herbs 0.5-1.5 m tall.
Leaves simple to pinnately compound, usually 6-19 cm long including petiole, leaflets 1-9, ovate-lanceolate, lanceolate, or narrowly lanceolate, usually 3.5-13.5 cm long, 0.5-6 cm wide, glabrous or pubescent, margins serrate, occasionally ciliate, apex acuminate.
Heads 15-75 or more in diffuse to congested, many-branched, compound cymes terminating main stem and lateral branches, 1.5-4.5 cm in diameter including ray florets, peduncles 0.1-4 cm long, glabrous or glabrate to densely pubescent; outer involucral bracts 1-2.5 mm long, the inner ones distinct; ray florets 3-9 per head, sterile, rays yellow, 7-25 mm long, 3-7 mm wide; disk florets 5-18 per head, perfect or pistillate (and then plants gynodioecious), corollas yellow; pappus of 1-2 awns 0.5-2.5 mm long or absent.
Achenes black, straight, curved or coiled, wingless or rarely winged in subsp. ctenophylla, 5-14 mm long, 0.7-1.5(-2) mm wide, glabrous.
[2n = 72*; subsp. ctenophylla.]