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

Habit
Erect perennial herbs; stems densely antrorsely strigose, becoming hirsute and glandular hirsute toward and throughout the inflorescence (hairs straight or slightly curved, 0.1-0.6 mm long). 

Leaves
Leaves rugose, ovate to broadly ovate, (15-)19-33 cm long, (6-)7.5-15.3 cm wide, both surfaces conspicuously (at least when dry) and usually densely glandular-dotted, upper surface appressed long-hirsute, lower surface hirsute to antrorsely strigose, densely so along veins, margins crenate, apex acuminate, base truncate to rounded or subcordate, petioles (5-)6-13.5 cm long, densely antrorsely strigose (in Wai`anae Mts. hairs usually spreading).  Flowers  

Flowers
Flowers (4)6 per verticillaster, in leafless, compound, racemose inflorescences usually 15-20 cm long, consisting of the terminal primary stem and numerous secondary and tertiary lateral branches immediately below, pedicels (5-)8-15 mm long, glandular hirsute and hirsute, bracts narrowly ovate to elliptic-ovate, 6-9 mm long; calyx campanulate, 3-6 mm long, nerves conspicuous, short-hirsute, glandular hirsute, and glandular-dotted, the teeth narrowly deltate to linear-deltate or linear-elliptic, 1.5-3 mm long, apex attenuate to acute; corolla white, purple-tinged, tube curved, ca. 9-13 mm long, glandular-dotted, short-hirtellous, and ± glandular hirtellous, upper lip ca. 2.5-3 mm long, lower lip ca. 6-9 mm long.   

Fruit
Nutlets ca. 3-6 mm long.