About Hypocalymma cordifolium Schauer
Hypocalymma cordifolium is most often a low-growing shrub, usually reaching a height of 0.2–2 m (7.9 in – 6 ft 6.7 in), but it may occasionally grow as an erect shrub up to 6 m (20 ft) high. Its young stems have prominent wings and sometimes show a deep red color. The species has heart-shaped leaves that measure 6–19 mm (0.24–0.75 in) long and 9–18 mm (0.35–0.71 in) wide; leaves are either sessile, or borne on a petiole up to approximately 0.5 mm (0.020 in) long.
Flowers are arranged in up to 16 leaf axils near the ends of branchlets, most commonly in groups of 2, though they sometimes occur singly or in groups of up to 4. Flowers grow on peduncles up to 1 mm (0.039 in) long, with green or red-tinged bracteoles 1.3–2 mm (0.051–0.079 in) long at the base of each flower. The sepals are broadly oblong to egg-shaped, 1.5–2.0 mm (0.059–0.079 in) long and 1.9–2.3 mm (0.075–0.091 in) wide, and are also green or red-tinged. Petals are white or pale pink, 2.5–4.5 mm (0.098–0.177 in) long, and there are between 25 and 45 stamens whose filaments are joined at the base.
Flowering occurs year-round, with a peak flowering period between September and November. The fruit is a capsule 1.5–1.7 mm (0.059–0.067 in) long, containing pearly white or pale brown seeds 1.1–1.3 mm (0.043–0.051 in) long. This Hypocalymma species grows in seasonally wet locations including creek beds and swamps, with a distribution ranging between Jarrahdale and Margaret River, extending east along the south coast to Cape Riche.
