Dacrydium magnus was first described by David de Laubenfels in 1969. It is synonymous with Dacridium beccari var. rudens also described by Mr. de Laubenfels in the same year.
Description. Dacridium magnus is an evergreen coniferous tree in the Podocarpaceae family that will grow from 25 to 100 feet (8 – 30 m) tall, and 2 to 24 inches (5 – 60 cm) in diameter. Its branches are dense, spreading, and upturned. Juvenile leaves spread widely, slightly curved forward at the tip, are pungent, and triangular in cross section, gracile, up to at least 0.7 inch (18 mm) long. Adult leaves spread at about a 45 angle and are strongly curved forward so that the spiny tip is parallel to the branch or bent slightly inward, forming a compact rope-like branch system, that is linear-lanceolate, 0.17 inch (3-6 mm) long but nearly uniform on a branch. Fertile structures mostly terminal but are occasionally found on short lateral branches, the subtending leaves hardly distinguishable from ordinary foliage leaves. Pollen cones are 0.4 to 0.6 inch (10 – 16 mm) long and 0.08 inch (2 mm) in diameter. The seed-bearing structure is formed of more or less straight and slightly spreading leaf-like bracts which cover the base of the seed. The ripe fruit reported to be brown but possibly an old fruit as has been observed in other species. Seed is 0.2 inch (5 mm) long, often with two seeds per cone.
Distribution. This species is native to Solomon Islands (Guadalcanal, Choiseul, south Ysabel); Louisiades (Sudest Island.) and Moluccas (Obi Island). Rare, but “locally common in the canopy of moist tropical forest between 200 and 3,800 feet (60 and 1200 m) elevation, often along ridge crests where it has a somewhat reduced stature”