Agathis is an important genus of about 20 species of large timber trees from southeastern Asia, Australasia and the Pacific islands, with one species in New Zealand that is described below. Trees may be 45–60 m in height with columnar trunks, with a single leader when young, forking when older. The bark contains resin canals, as do the leaves, which makes them brittle and easily snapped. The opposite or subopposite leaves have short petioles and are usually lanceolate to ovate or elliptic, leathery, and often glaucous; both within an individual tree and at the species level, however, the leaves can be very variable in shape. Agathis are monoecious, but produce female cones before the males. The male strobili are more or less sessile, cylindrical, composed of a number of bracts that produce the microsporophylls. The female cones are massively globose and borne on shoot tips, with tightly appressed scales, each with a single ovule. The cones shatter at maturity. The seed is a flattened ovoid, with one large wing and sometimes a second smaller wing (Whitmore 1980).
Agathis is almost entirely unknown to temperate gardeners, being a typical rain-forest genus. In New Zealand the indigenous Kauri, Agathis australis, which used to be an important forest species, has been extensively logged, reducing an original extent of perhaps 1.2 million hectares to just 140 hectares. Regeneration is very slow, and would naturally occur after severe disturbance that removes competition. The species is now grown elsewhere for timber (Marinelli 2004).
A number of other Agathis species are described by Krüssmann (1985b), but are not known to have been cultivated outside in our area. A fascinating account of early introductions of Agathis to horticulture has been given by Mabberley (2002).