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 Kaua`i, O`ahu, Moloka`i, Lana`i, Maui, Hawai`i.

Habit
Erect to sprawling subshrubs; stems terete, 3-20 dm long, glabrous or sometimes short-hirtellous in the inflorescence, often glaucous.

Leaves
Leaves usually widely spaced, firm-coriaceous, narrowly to broadly ovate, cordate, or oblong-ovate to oblong-lanceolate, (4-)6-16.5 cm long, (1-)2.5-5.5 cm wide, lateral veins usually impressed on upper surface, strongly to slightly raised on lower surface, higher order venation inconspicuously to somewhat conspicuously reticulate, not or slightly raised on lower surface, glabrous or lower surface short-hirtellous along midrib, sometimes along most veins, rarely spread more evenly over lower surface, apex acuminate to long-acuminate, sometimes caudate, base cordate to subcordate, petioles winged, 0-1 cm long, stipules broadly deltate, ca. 4-10 mm long, adnate to inner side of petioles, apex with a mucro 0.3-2(-3) mm long. 

Flowers
Flowers perfect or functionally pistillate, in somewhat stiff, usually narrow, decussate, interrupted, thyrsoid, paniculate inflorescences, lateral branches terminating in compact or sometimes loose cymes, inflorescences glabrous or hirtellous throughout, pedicels ca. 3-5 mm long; hypanthium turbinate to urceolate-turbinate, ca. 1.5 mm long, glabrous or sometimes short-hirtellous; calyx lobes narrowly deltate to oblong, 1-3.5 mm long, enlarging slightly in fruit, glabrous or short-hirtellous, apex acute or obtuse; corolla purple to violet, throat green to yellowish green, fleshy, salverform, the tube 9-15(-20) mm long, glabrous or densely short-hirtellous, the limb strongly quadrangular in bud, apex not depressed, the lobes 3-7 mm long, reflexed or, if spreading, then usually quickly reflexed as anthesis proceeds, apex of each lobe ± with an inconspicuous appendage; style hirtellous or pilose in lower part or nearly throughout, rarely glabrous, 2-lobed. 

Fruit
Capsules turbinate to subglobose, slightly compressed, strongly grooved and appearing somewhat didymous, 3-5 mm long, 3.5-7 mm in diameter, dehiscing loculicidally across disk, pyrenes separating septicidally, but remaining in the persistent vascular skeleton of the mesocarp, endocarp sclerified, disk flat or slightly raised, grooved. 

Seeds
Seeds pale brown, irregularly cuneiform, strongly compressed, conspicuously winged, minutely rugulose.

 

Seeds
2n = ca. 100*