Description from Flora of China
Trees or shrubs evergreen, monoecious; branchlets arranged in a plane, flattened. Leaves 4-ranked, scalelike, base decurrent only on leading branchlets, dimorphic along branchlets: facial pairs obovate-rhombic; lateral pairs boat-shaped, ridged abaxially, less than 4 mm, overlapping facial pairs, without conspicuous, white stomatal bands abaxially. Pollen cones with (4 or)6-10(-16) microsporophylls, each with (2 or)3 or 4 pollen sacs. Seed cones terminal, solitary, dehiscent when mature in 1st year; cone scales 8 or 10, decussate, flat, only middle, larger 2 or 3 pairs fertile, each fertile scale bearing 1 or 2 seeds; free bract apex a very short mucro. Seeds flat, with 2 lateral, narrow wings. Cotyledons 2.
Five species: E Asia, E and W North America; five species (one endemic, three introduced) in China.