Description

Key Characters:

Growth Form: Small trees 3–6 m tall.

Stems: Trunks to 30 cm dbh, bark smooth, light tan to gray. Stems many branched. Young branchlets densely white to tan pubescent with 8–12–rayed stellate trichomes 0.3–0.4 mm in diam. surface scurfy–waxy, glabrescent with age, petiole scars prominent, subcircular, 2.5–4 mm in diam.

Roots:

Leaves: Leaves simple. Alternate. Blades broadly–ovate to suborbicular or subreniform in outline, occasionally shallowly 3–lobed, 7.5–16(–18) cm long, (8)9.5–13.5(–18) cm wide. Apex acute to obtuse or rounded. Base cordate, with a wide to narrow but usually open sinus. Surfaces of new growth densely stellate–pubescent; green when fresh with scattered tan stellate pubescence, densely so along veins and upper surface, trichomes 0.2–0.4 mm in diam. with (2–)8–16 rays; lower surfaces with principal vein axils domatiate with dense tufts of tan to white trichomes 0.2–0.3 mm long. Blades chartaceous. Margins irregularly broadly crenate. Veins prominulous, primary veins 7–9 radiate from base, midvein with 3–4 pairs of secondary veins arising along midrib, light green to occasionally red tinged when fresh, higher order venation prominulous on both surfaces. Petioles 3.5–6 cm long, green or sometimes red–tinged, pubescent with dense white to tan stellate trichomes as on branchlets. Stipules lanceolate to subulate, 2–3.5 mm long, apex acute, green, sparsely to densely tan or white stellate pubescent, soon caducous.

Flowers: Flowers solitary, axillary, erect to spreading, pedicels 22–30 mm long, green or sometimes red–tinged, densely white to tan stellate pubescent as in petioles, involucral bracts 5–6 (–7), linear–subulate to lanceolate (rarely spathulate), acute to acuminate apically, connate only at base, 9–22 mm long, 1–2 mm wide at base, erect, appressed or spreading perpendicular to the floral axis in anthesis, green, densely tan or white stellate pubescent with trichomes 0.2–0.3 mm in diam. Flowers bisexual (perfect). Calyx tubular–saccate, mostly 5-lobed, tube 22–30 mm long, 19–20 mm wide, the lobes triangular, acute to short acuminate 5–10 mm long, 7–8 mm wide, green, surface obscured by dense tan stellate pubescence as in bracts, in mature fruit splitting along one side but persistent. Corolla zygomorphic, adaxially curved, 5–6.5 cm long, lobed nearly to base, lobes coalescent, 6–6.5 cm long, 3.5–4 cm wide, obovate–spathulate, apex obtuse, tips and outer margins slightly reflexing with age, outer exposed portion purple, purple–green or purple–yellow, inner stellate trichomes especially along veins, internally yellow or purple–tinged distally, purple toward base, corolla usually becoming purplish with age. Stamens monadelphous, forming staminal column and apex of the style exserted for 1.5–2.5 cm; staminal column 8–8.5 cm long; antheriferous in distal 3.5 cm, maroon–purple; antheriferous in distal 3.5 cm, Stamens c. 100; anthers reniform-curved, 0.8–1.5 mm long, purple; filaments 6–12 mm long, purple; anthers monothecal. Pollen grains purple turning golden yellow after anther dehiscence; globose, echinate. Ovary superior, dome-shaped, 8 mm long and wide, placentation axile, 5-celled; ovules (2)3 per cell; style 8.5–9 cm long exceeding the staminal column, branches 5, 3–5 mm long, villose; stigmas rounded, c. 1 mm long, yellow, ovary dome–shaped, 8 mm long and wide.

Fruit: Fruit a woody capsules; globose–cuboid to –ovoid; 5–locular; 5–valved; 2.5–3.5 (–4) cm long; 2.2–3.3 cm in diameter; surface yellowish brown; rough densely covered with dense tan stellate hair clusters; appearing tuberculate; mericarps 10; mesocarp well developed; reticulate; endocarp chartaceous; loose; with scattered long hairs; testa brown. Seeds 1–2 per mericarp; reniform; 8–10 mm long; 6–8 mm wide including the dense; lanate yellowish–tan hairs 0.4–1 mm long; with or without endosperm.

Ploidy:

Habitat: Occurs on very steep; rocky slopes. These sites have a windward aspect and are situated mid–slope between the upper rim of a deep valley and a perennial stream below. Soils at these sites are of typical volcanic; basalt origin; from the Wailuku Series of original shield building flows. The vegetation where Hibiscadelphus stellatus grows forms a mosaic of trees and shrublands with an open canopy; best characterized as Lowland Mesic Forest (Wagner et al. 1999). Rainfall averages from 12 to 1400 mm annually and the substrate is well–drained.

Elevation Range: 800–900 m.