Description

Key Characters:

Growth Form: Small, many-branched shrubs 6–12(–18) dm tall, pubescent with simple hairs.

Stems:

Roots:

Leaves: Leaves simple. Alternate or rarely opposite; crowded at the ends of the branches. Blades usually elliptic, occasionally lanceolate or oblanceolate, 6–17 cm long, 0.6–4 cm wide. Surfaces glabrous, blades , thin, not fleshy. Margins serrate to base, the teeth acuminate to acute, rarely obtuse. Petioles 1–4 cm long. Stipules absent.

Flowers: Flowers usually bractless in paniculate racemes, puberulent, the branches subtended by linear, leaf-like bracts 2–3 cm long. Flowers bisexual (perfect), actinomorphic or rarely slightly irregular; white, pale yellow, or greenish, usually 2–3 mm long, sometimes absent. Calyx of 4 sepals, deciduous, erect, usually oblong, sometimes the inner 2 with gibbous bases that hold the nectar; obovate to subspatulate, 0.8–1.2 mm long, conspicuously white–margined, the greenish part densely puberulent. Corolla of 4 petals, rarely absent, yellow, white, or lavender, entire to emarginate, rarely lobed or fimbriate, usually with an elongate claw; 1–1.5 mm long. Stamens 6, longer than petals, the inner 4 usually in pairs, sometimes connate at base in pairs; anthers dithecal, opening by longitudinal slits. Ovary superior, 2(4?)-carpellate, usually 2-celled by means of a false, but usually complete septum, rarely 1-celled, sessile or rarely stipitate; ovules 1 to numerous, borne on parietal placentas on replum margin at periphery of ovary wall, campylotropous or occasionally anatropous; styles short or essentially absent; stigma capitate.

Fruit: Capsules divided into 2 cells by the usually thin and membranous septum; elongate (at least 3 times as long as wide) and referred to as a silique; depressed–orbicular; wider than long; 2.5–3.1 mm long; 4–4.5 mm wide; apex not notched; the surface conspicuously roughened. Seeds 1 to numerous; reddish brown; suborbicular; 1.6–2 mm in diameter; with think winged margins; the wing ca. 0.1 mm wide; often becoming mucilaginous when wet; endosperm essentially absent.

Ploidy: 2n = 32*

Habitat: Scattered on rocky ledges and cliffs in mesic forest from widely scattered localities on Kaua‘i.

Elevation Range: (450–)610–1,160 m.