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 Nihoa, Kaua`i, O`ahu.
Leaves Leaves not especially thick, lanceolate to narrowly deltate, (8-[Nihoa])11-33 cm long, 2.8-11 cm wide, upper surface glabrous or rarely sparsely short-pilose, and then especially along veins, lower surface sparsely to moderately pilose, or glabrous in some O`ahu and Nihoa plants, margins usually undulate, crisped, and erose-denticulate, rarely (Nihoa) subentire and apparently not crisped, apex acuminate to long-acuminate, base cordate, sometimes base of upper leaves (especially Nihoa plants) broadly cuneate, petioles 1.5-9 cm long.
Flowers Flowers unisexual (and the plants monoecious), the proportions of each sex varying from nearly equal to one type strongly dominating, numerous in diffuse, green or yellowish green, many-branched, paniculate inflorescences (12-)15-50 cm long; staminate flowers with outer tepals green, 2-2.5 mm long, the valves yellowish green, membranous, 3-3.5 mm long, anthers 1.8-2 mm long; pistillate flowers with outer tepals green, 0.8-1 mm long, the valves yellowish green, membranous, 1.2-1.5 mm long, enlarging to 5-7 mm long and becoming cordate in fruit, venation becoming conspicuous, the faces without tubercles.
Fruit Nuts pale brown, 2-2.4 mm long, usually slightly wider, the 2 sides of a single arm of a mature nut subparallel, the angle very narrowly acute, margins of arms without a conspicuous thickened rim.