Flora of the Hawaiian Islands
Dicotyledon Literature for Bidens macrocarpa
Wagner et al., 1990, 1999.
   Asteraceae -- The Sunflower Family Bibliography
      Bidens macrocarpa
General Information
DistributionIn the Hawaiian Islands, endemic to O`ahu.

Asteraceae - Bidens macrocarpa

Click here for detailed USGS map by Jonathan Price
Erect, suffrutescent perennial herbs 0.5-2 m tall, with horizontal lateral branches.
Leaves pinnately compound or partly bipinnately compound, usually (6-)9-26 cm long including petiole, leaflets 3-7, coriaceous, ovate-lanceolate, usually 4-9 cm long, 2-5.5 cm wide, sparsely pubescent at least on veins, margins serrate.
Heads 5-30 in compound cymes terminating lateral branches only, 3-4.5(-5) cm in diameter including ray florets, peduncles 1-3 cm long, sparsely pubescent; outer involucral bracts 4-8 mm long, the inner ones distinct; ray florets 5(-7) per head, sterile, rays yellow, 20-26 mm long, 7-8 mm wide; disk florets 9-20(-26) per head, perfect, corollas yellow, occasionally with black tips on lobes; pappus of 1-2(3) awns 0.5-1.5 mm long, often irregularly developed and decurrent into the margins of the achene.
Achenes brown, straight or slightly curved but not twisted, narrowly winged, (7-)11-20 mm long, 1.5-2.8 mm wide, glabrous or sparsely setose on margins.
2n = 72*