2. Agathis Salisbury, Trans. Linn. Soc. London, Bot. 8: 311. 1807.
贝壳杉属 bei qiao shan shu
Trees monoecious; branches usually whorled on young trees, becoming irregularly arranged on mature ones, with orbicular scars of deciduous branchlets; winter buds globose, small. Leaves spirally arranged on main branches, opposite or alternate on lateral branchlets, leaving cushion-shaped scars on falling, pinkish or reddish when young, finally dark green, greatly variable in size and shape even on same branchlet, leathery, with numerous, indistinct, parallel, thin veins; petiole flattened, short. Pollen cones axillary, solitary, upright, cylindric, hard; microsporophylls densely arranged. Seed cones globose or broadly ovoid; bracts densely arranged, flabellate, apex thickened. Seeds detached from bracts, with a lateral wing on 1 side and a small protrusion (occasionally developed into a wing) on other. Cotyledons 2.
Twenty-one species: Indonesia, Malaysia, Papua New Guinea, Philippines; Australia, New Zealand, SW Pacific Islands; one species (introduced) in China.