Description

Key Characters:

Growth Form: Erect perennial herbs.

Stems: Stems quadrangular, 3–6 dm long, densely white tomentose.

Roots:

Leaves: Leaves simple. Opposite. Blades narrowly cordate, 8–17 cm long, 3–5.5 cm wide. Apex obtuse to acute. Upper surfaces densely puberulent, green, rugose; lower surfaces densely white tomentose; blades somewhat fleshy. Margins crenate. Petioles 2.5–5 cm long. Stipules absent.

Flowers: Flowers subsessile, in simple, often dense, terminal racemes, 2 flowers per verticillaster, 10–30 cm long, bracts oblong-lanceolate, usually 4–6 mm long, lowest pair up to 20 mm long. Calyx actinomorphic, cylindrical, closed at maturity or nearly so, 8–12 mm long, densely tomentose, 5-toothed, the teeth linear (2–)3–5 mm long, splitting longitudinally, usually persistent or sometimes only ventral 1/2 persistent. Corolla zygomorphic, bilabiate, white or sometimes tinged purple externally; tube narrowly funnelform, somewhat curved, ca. 14–22 mm long, upper lip 8–10 mm long, lower lip 10–14 mm long, the lobes suborbicular, middle lobe largest, margins strongly undulate-crisped; nectary disk often present at base of ovary, annular or developed on anterior side only. Stamens 4, both pairs of similar length or the upper pair slightly longer, ascending under the upper lip, included; filaments inserted near the throat; anthers dithecal; anther sacs divaricate, opening by longitudinal slits. Ovary superior, 2-carpellate, placentation basal-axile; ovules 1 per ovary lobe; style 1, included, shortly 2-lobed, the lobes clavate, pubescent in upper part; stigmatic only at the truncate apex, 1 lobe often rudimentary; stigmas 2.

Fruit: Nutlets 1-seeded; dark brown; ca. 3.5–4 mm long; truncate at both ends; apex sparsely tomentose; enclosed in the persistent closed calyx; pericarp thick and hard. Seeds with endosperm absent or scanty and oily.

Ploidy:

Habitat: Formerly known from barren ridges; Kaua'i; sandy isthmus and Kula; Maui; and ; Nohonaohae Cinder Cone; Pu'ukapele; and Waiki'i; Hawai'i. Presently known only from Kipukakālawamauna; Hawai'i.

Elevation Range: 990–2,135 m.