Allocasuarina acutivalvis

Allocasuarina acutivalvis is a dioecious shrub to small tree that typically grows to a height of 3–8 m (9.8–26.2 ft). The branchlets are erect, up to 200 mm (7.9 in) long, the leaves reduced to erect, scale-like teeth 0.3–1.3 mm (0.012–0.051 in) long, arranged in whorls of 10 to 14 around the branchlets. The sections of branchlet between the leaf whorls (the "articles") are 10–25 mm (0.39–0.98 in) long and 0.7–1.2 mm (0.028–0.047 in) wide. The flowers on male trees are arranged in spikes resembling a string of beads 10–80 mm (0.39–3.15 in) long, the anthers 1.2–2.1 mm (0.047–0.083 in) long. The female cones are covered with fine, white hairs when young, and are sessile or on a peduncle up to 10 mm (0.39 in) long. Mature cones are 15–35 mm (0.59–1.38 in) long and 15–28 mm (0.59–1.10 in) in diameter, the samaras black or dark brown and 6–12 mm (0.24–0.47 in) long.

Allocasuarina acutivalvis grows in tall heath and open woodland, sometimes on rocky hillsides, and is widespread in the south-west of Western Australia from north of the Murchison River to Zanthus. Subspecies prinsepiana occurs from near Mullewa to near Merredin, surrounded by and sometimes intergrading with subsp. acutivalvis.