Leaf Anatomy of Wollemi Pine (Wollemia nobilis, Araucariaceae)

Abstract

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