Flora of the Hawaiian Islands
Dicotyledon Literature for Hydrangea arguta
Wagner et al., 1990, 1999.
   Hydrangeaceae -- The Hydrangea Family Bibliography
      Hydrangea arguta
General Information
DistributionIn the Hawaiian Islands, endemic to Kaua`i, O`ahu, Moloka`i, Lana`i, Maui, Hawai`i.















Click here for detailed USGS map by Jonathan Price
Habit
Shrubs 2-5 m tall; stems with conspicuous deltate to subrhombic leaf scars, hirsute, becoming glabrate.
Leaves
Leaves opposite or in whorls of 3 per node, coriaceous, oblong-elliptic, elliptic, or oblong-oblanceolate, 10-32 cm long, 3-9.5 cm wide, those of vegetative shoots often larger and broader, upper surface with conspicuously impressed veins, sparsely hirsute, glabrate with age, lower surface with slightly raised veins, sparsely to densely hirsute, primarily along veins, margins crenate-serrate, each tooth with a blunt forward appressed lobe or mucro, outer margin of each tooth revolute, apex acute to obtuse or acuminate, base cuneate to attenuate, petioles 0.3-4(-8) cm long, dilated at base.
Flowers
Flowers in corymbose panicles usually 5-7 cm long, ca. 8-12 cm wide, the branches subtended by foliaceous sessile bracts 12-25 mm long, caducous, staminate inflorescences deciduous after anthesis; staminate flowers 5(6)-merous, sepals lanceolate, the lobes 1-5 mm long, petals greenish blue, pink to greenish white, yellow, or cream-colored, ovate, 3.5-8 mm long, staminal filaments unequal, 1-11 mm long, anthers purple to brown, pistillode nearly superior, 2-5 mm long, with ovules and a well-developed style and stigma, but these nonfunctional; pistillate flowers 5(6)-merous, sepals connate more than 1/2 their length and adnate to ovary, the lobes lanceolate to ovate, 1-4 mm long, petals greenish blue to pink, triangular, 0.5-3 mm long, stamens absent, ovary urceolate, 5.5-6 mm long, style 0.5-3 mm long.
Fruit
Fruit red to maroon, broadly ellipsoid to subglobose, 8-12 mm long, the flesh whitish.
Chromosomes
2n = 32*