Agathis are trees, with resin canals in the bark and leaves. Leaves are subopposite to opposite, narrowly
to broadly elliptic, leathery, with many more or less parallel nerves (Plate lOa). They are monoecious but
dichogamous. Male cones are borne in or slightly above the leafaxils, sessile or nearly so, and cylindric;
cone scales are peltate, numerous, each abaxially with 10-12 pollen sacs. Female cones (Plate 10) are
terminal, ovoid to globose, with numerous woody cone scales each bearing a single large ovule abaxially; the
cones become massive and woody at maturity; viable seeds form only in the centre of the cone. The seeds
are flattened-ovoid with 1 large wing and sometimes a smaller one. Ripe cones shatter on the tree.