It is a small evergreentree, 4–12 m (rarely to 20 m) high, with a trunk up to 50 cm diameter. The leaves are scale-like, 2–6 mm long and 0.5 mm broad, arranged in decussate whorls of three on very slender shoots 0.7–1 mm diameter. The cones are globose, 1–2 cm diameter, with six triangular scales, which open at maturity to release the seeds.
Some authors (e.g. Thompson & Johnson 1986, followed by the Flora of Australia Online) divide it into three species (or occasionally as varieties), based largely on the foliage colour, with green plants predominating on the east coast of Australia, and glaucous plants in the interior, and on cone size, with on average marginally smaller cones in tropical areas (north of 22°S). However, others (e.g. Blake 1959, Farjon 2005) point out that both the foliage colour and cone size is very variable, even from tree to tree in local populations, and maintain that it is impossible to distinguish three taxa within the species. When split into three species, the following names apply: