Description
Key Characters:
Growth Form:
Shrubs or small trees 2–8 m tall.
Stems:
Stems many-branched, glabrous, branches somewhat drooping, bark brown.
Roots:
Leaves:
Leaves simple.
Alternate.
Blades deltate–lanceolate to ovate or narrowly elliptic–lanceolate, (9.5–)15–36 cm long, (3.2–)4–12 cm wide.
Apex acuminate, sometimes bluntly acute.
Base broadly cuneate to truncate, sometimes (hawaiʻi) cuneate.
Upper surfaces glabrous; lower surfaces sparsely short–hirtellous along the veins or glabrous, sometimes (Maui and Hawai'i) pubescent over entire surfaces but more densely so along the veins; Leaves dark green, sometimes (Kauaʻi) with red veins and petioles, chartaceous to firm chartaceous, usually palmately, cystoliths usually prominent, especially on lower surface.
Margins usually undulate and irregularly crenate, crenate–serrate, or sometimes subentire.
Palmately 3-veined, 3-veined at base, with 12–15 additional pairs of pinnate veins.
Petioles 2–14.5 cm long, glabrous or short-hirtellous.
Stipules membranous, lanceolate and usually somewhat falcate, 3–4.5 cm long, glabrous.
Flowers:
Flowers in dichotomous, widely spreading, paniculate cymes arising from the lower leaf axils or at nodes below the leaves. staminate cymes: 3–9 cm long, peduncles 0.5–2.5(–3.5) cm long, each inflorescence branch terminated by a glomerule of 5–15 (–20) sessile flowers; pistillate cymes more delicate than staminate ones, (2.5–)3–9(–11) cm long, peduncles 0.8–3(–4) cm long, each inflorescence branch terminated by a green glomerule of 5–10 subsessile flowers, the interior pair somewhat wider.
Flowers unisexual (and the plants dioecious).
Calyx iof staminate flowers greenish white, sometimes tinged violet or on Kauaʻi lavender to pink or red, depressed–globose, lobes 4–5, ovate, hooded, 1.7–2.1 mm long, apex ciliate. Calyx of pistillate flowers green, ovoid–ellipsoid, slightly compressed, lobes 4, elliptic–ovate, unequal, concave, 0.6–0.8 mm long, ciliate toward apex.
Corolla (petals) absent.
Stamens in staminate flowers white or on Kauaʻi purple to pink; filaments incurved in bud, elastically reflexed when pollen is shed; anthers dithecal, opening by longitudinal slits; pistillate cymes: staminodes absent.
Ovary superior (pistillate cymes), psuedomonomerous, 1-celled; ovule 1, placentation basal; style 1; stigma large. Staminate flowers with ovoid pistillode, 0.3 mm long; ovary vestigial and sterile.
Fruit:
Achenes ovoid; slightly compressed; 1.8–2.2 mm long; completely enclosed by the orange or yellow; enlarged;fleshy calyx 2.5–3 mm long; the surface with prominent cystoliths and scattered transparent glands.
Seeds 1 per achene.
Ploidy:
Habitat:
Slopes and gulch bottoms in mesic to wet and diverse mesic forests.
Elevation Range:
150–1700 m.