Hypocalymma serrulatum

Hypocalymma serrulatum is an erect shrub that typically grows to a height of 0.3–1.8 m (1 ft 0 in – 5 ft 11 in). Its leaves are linear in outline, 6–15 mm (0.24–0.59 in) long, 0.8–1.3 mm (0.031–0.051 in) wide and 0.5–0.8 mm (0.020–0.031 in) thick. The upper side is grooved, the lower side deeply convex with one or two rows of oil glands and the edges of the leaves have small serrations. The flowers are 7–8 mm (0.28–0.31 in) in diameter, and often arranged in pairs with bracteoles 2–3 mm (0.079–0.118 in) long at the base. The floral tube is about 3–4 mm (0.12–0.16 in) wide and the sepals are broadly egg-shaped, 1.5–2.2 mm (0.059–0.087 in) long and 1.8–2.7 mm (0.071–0.106 in) wide. The petals are white or pink, 3.0–3.5 mm (0.12–0.14 in) long and there are 40 to 55 white stamens, the longest filaments 3.5–5.5 mm (0.14–0.22 in) long. Flowering occurs in most months with a peak from March to July, and the fruit is a capsule 3.5–4.0 mm (0.14–0.16 in) long and 4–5 mm (0.16–0.20 in) in diameter.^[2][3][4]

Hypocalymma serrulatum was first formally described in 2003 by Arne Strid and Greg Keighery in the Nordic Journal of Botany from specimens Keighery collected 9 km (5.6 mi) east-north-east of Badgingarra in Badgingarra National Park in 1982.^[3][5] The specific epithet (serrulatum) means 'like a small saw', referring to the edges of the leaves.^[6]