Wagner, Warren L., Derral R. Herbst and S. H. Sohmer. 1999. Manual of the Flowering Plants of Hawai'i (Bernice Pauahi Bishop Museum Special Publication, 2 Vol. Set). Honolulu, HI
Flora of Hawaii:
Distribution In the Hawaiian Islands, endemic to O`ahu.
Habit Erect, suffrutescent perennial herbs 1-2.5 m tall, with horizontal or ascending lateral branches.
Leaves Leaves pinnately or bipinnately compound, usually 9-30 cm long including petiole, leaflets 3-9, ovate-lanceolate to narrowly lanceolate or nearly linear (in bipinnately compound forms), usually 2.5-13 cm long, (0.5-)1.5-6 cm wide, young leaves white, golden, or rusty pubescent, margins serrate.
Flowers Heads more than 50 in many-branched compound cymes terminating lateral branches only, 1.5-3.5 cm in diameter including ray florets, peduncles 0.4-2.2 cm long, white, golden, or rusty pubescent; outer involucral bracts 1.5-3.5(-4) mm long, the inner ones distinct; ray florets (3)4-6 per head, sterile, rays yellow, 8-21 mm long, 4-7 mm wide, often smaller on female plants; disk florets 11-22 per head, perfect or female(and then plants gynodioecious), corollas yellow; pappus of minute awns or absent.
Fruit Achenes black, strongly twisted to tightly coiled up to 4 revolutions or irregularly contorted, wingless, 2.5-10(-13) mm long (short lengths because of coiling), 0.5-1 mm wide, glabrous.