Description
Key Characters:
Growth Form:
Subshrubs up to 2 m tall.
Stems:
Stems much-branched, quadrangular, densely strigose, downy-hairy.
Roots:
Leaves:
Leaves simple.
Opposite, each pair at right angles to the next.
Blades broadly ovate, 6–29 cm long, 5–28 cm wide.
Apex acute.
Base cordate to truncate.
Surfaces sparsely to moderately strigillose; blades membranous.
Margins coarsely and irregularly dentate, sometimes weakly 1–3-lobed.
Petioles 2–23 cm long.
Stipules absent.
Flowers:
Flowers numerous in dense, terminal, cymose inflorescences, often subtended by a pair of foliaceous bracts, bracteoles numerous, oblong or elliptic, 1.5–3 cm long, strigillose, especially along the margins.
Flowers bisexual (perfect) or sometimes unisexual (and then plants gynodioecious or rarely dioecious), fragrant.
Calyx purple or red, sometimes with white spots, campanulate, 10–15 mm long, deeply 5-lobed, the lobes lanceolate, apex acuminate.
Corolla nearly actinomorphic or slightly irregular, pale pink or white, salverform, usually doubled by petaloid stamens, 5-lobed, the lobes subequal; tube ca. 0.5" long, limb ca. 1" diam.; nectary disk often present at base of ovary, annular or developed on anterior side.
Stamens 4(5), in 2 pairs, inserted on corolla tube and usually long–exserted, aligned with the sinuses, usually modified as petals.
Ovary superior, usually modified into extra petals, 4-celled, placentation axile; ovules 1 per cell, attached laterally, erect, anatropous; style 1, usually modified as petal.
Fruit:
Fruit unknown.
Seeds unknown.
Ploidy:
2n = 46; 52
Habitat:
Naturalized in open; wet; partly shaded; disturbed areas at the edges of mesic and wet forest; taro paddies; or streams.
Elevation Range:
50–670 m.