Leaf anatomy of Wollemi pine (Wollemia nobilis, Araucariaceae)

Leaves of adult morphology from Wollemi pine (Wollemia nobilis W.G. Jones, K.D. Hill and J.M. Allen) possess a thick cuticle, sunken stomata, abundant hypodermal fibres, distinct palisade and spongy mesophyll with most palisade development on the adaxial side, compartmented cells, resin canals, sclereids, and vascular bundles with transfusion tissue and a fibre cap abaxial to the phloem. Stomata are present on both leaf surfaces, although in greater density on the abaxial surface, and usually have an oblique orientation and four or five subsidiary cells. At the light microscope level, Araucaria can be distinguished from Agathis as it possesses unusual compartmented cells in the mesophyll, while Agathis does not. In addition, most Agathis species are hypostomatic, while most Araucaria species have stomata on both the abaxial and adaxial surfaces. Thus W. nobilis has a leaf anatomy which has a greater similarity to Araucaria than to Agathis.