Flora of the Hawaiian Islands
Dicotyledon Literature for Bidens cosmoides
Wagner et al., 1990, 1999.
   Asteraceae -- The Sunflower Family Bibliography
      Bidens cosmoides

Common name(s): beggartick, ko`oko`olau, ko`olau, Spanish needle, Po`ola nui (Kaua`i)
General Information
DistributionIn the Hawaiian Islands, endemic to Kaua`i.
















Click here for detailed USGS map by Jonathan Price
Habit
Scandent, suffrutescent perennial herbs 1-2.5 m tall, with spreading, sometimes rooting branches.
Leaves
Leaves pinnately compound, usually 9-33 cm long including petiole, leaflets 3-9, lanceolate to ovate-lanceolate, usually 4-14 cm long, 1.5-6 cm wide, sparsely pubescent, margins serrate and ciliate.
Flowers
Heads 1-3 in cymes terminating lateral branches only, (5-)6-8 cm in diameter including ray florets, pendant and campanulate, peduncles 5.5-15 cm long, sparsely pubescent; outer involucral bracts foliaceous, 15-25 mm long, margins ciliate, the inner ones distinct; ray florets 7-19 per head, sterile, rays yellow, 30-52 mm long, 10-15 mm wide; disk florets (12-)20-40(-50) per head, perfect, corolla tube reddish orange, the lobes dark yellow; anthers black, 4-6 mm long, exserted beyond corolla tube; styles long, exserted 10-30 mm beyond the anthers; pappus of 2 awns up to 1 mm long or absent.
Fruit
Achenes dark brown, irregularly curved or contorted, wingless, 8-14 mm long, 1-1.5(-2) mm wide, setose, each achene enveloped by the subtending chaffy receptacular bract.
Chromosomes
2n = 72*