The genus Araucaria contains some of the most distinctive trees in existence, including the widely grown A. araucana, the Monkey-puzzle, and the Norfolk Island Pine A. heterophylla, whose whorled branches are so familiar a sight in tropical gardens. There are 19 species in the genus, with a scattered distribution in former Gondwanaland (although they occurred in Laurasia as well). Two are from South America, while the others are from a cluster of localities in Australasia centred on New Caledonia, where an astonishing 13 species occur as endemics or near endemics. All are substantial trees, with a stout, straight and usually unbranched main trunk bearing similarly stout, spreading branches, in whorls. The bark is resinous. In youth the branches occur from the base, but in maturity the lower branches usually senesce, leaving the tree with an often ragged-looking crown. The branches are clad along their length with stiff evergreen scale leaves, varying from small and needle-like to broad and rigid, usually sharp-tipped. Buds are indistinct among the foliage. The trees are usually dioecious, but hermaphrodites sometimes occur, and are self-fertile. Male strobili are solitary or clustered, forming dense cylindrical ‘cones’ borne upright from the branches. Female cones are large and globose, formed of many scales which fall apart at maturity, persisting for two to three years on the tree. Each scale has one (usually winged) seed adherent to it (Dallimore et al. 1966, Krüssmann 1985b, Farjon 2001).
The Monkey-puzzle Araucaria araucana – so beloved of the Victorians, and still commonly planted – is generally appreciated and reviled in about equal measure. It must be said that a solitary scrawny specimen in a suburban setting is not an inspiring sight, but a well-grown young one is a handsome object and with thoughtful modern planting around it, need not appear so out of place as it often does. It is the regular branching that makes the tropical and subtropical species of Araucaria so attractive when young, and gives the impetus to attempts to grow them in our area. In addition to the species described below, A. cunninghamii D. Don from Australia (Queensland) and New Guinea may be worth attempting in mild coastal gardens, having reached 18 m at Penjerrick, Cornwall in the much cooler past (1928 record, TROBI). Araucaria hunsteinii K. Schum. from New Guinea is in cultivation at Tregrehan, where a young tree is growing steadily. Although Krüssmann (1985b) describes several other tropical species, there is no evidence that these have ever been cultivated outdoors in our area, and they are omitted from our cross-references. Propagation is by seed.
From Bean's Trees & Shrubs
An important genus of conifers with some ten species in the southern hemisphere. It is represented in S. America by the species described below; and by A. angustifolia of S.E. Brazil and neighbouring parts of Argentina, known as the Parana pine. The other species are natives of Australia, New Guinea, and islands of the S.W. Pacific. Of the two Australian species, A. bidwillii and A. cunninghamii, the latter is an important forestry tree, and both are planted for ornament in frost-free climates. Still better known as a specimen tree is the Norfolk Island pine, A. heterophylla (excelsa), but this, too, is not hardy enough in Britain.
All the species are characterised by evergreen leaves which persist on the branches for many years; in the two S. American species, and in A. bidwillii, they are flat and broad, in the others more or less linear or awl-shaped. The former group is also distinguished by its larger cones.
The family Araucariaceae is a small one, comprising, besides Araucaria, only the genus Agathis, with some twenty closely allied species in New Zealand, the S.W. Pacific and Malesia. Of these the best known is the Kauri pine, Agathis australis, native of the northern extremity of the N. Island of New Zealand.