292 



II. SYSTEMATIC. 



A shrub with fastigiate branches, having closely packed, glabrous, rigid 

 branchlets. Leaves varvang in si^e according to the age of the dependent branch, 

 graduating from the acicular form of primordial leaf to a comparatively long 

 decurrent one on the smaller uppermost branchlets. the free ends spreading. 



Male amentum short, about 4 mm. long ; microsporangia orbicular, obtuse. 

 Female amentum at lirst consists of a series of scales (five or six) in whorls of three 

 each, all imbricate ; as these develop the two uppermost whorls of scales become 

 sporophylls and b\' a process of adnation at the base form the cone, which is then 

 composed of six equal, valvate valves, with one or two seeds at the base of each, 

 and several imbricate scales on the back. The shape of the cone is rather inclined 

 to elongation from a sphere, or say conical, measuring ^ inch in diameter; the 

 whole being permeated with oil cavities. 



III. LEAVES. 



(a) Economic. 



(None known, except chemical constituents.) 



(b) Anatomy. 



A cross-section through the three decurrent leaves gives a distinctive outline 

 from that obtained from a corresponding section in the Callitris, the dorsal surface 

 is marked by a pronounced ridge, at the base of which are situated the stomata 

 in longitudinal lines, the collateral ventral surfaces of the leaves only appearing 

 in this case to be transpiratory at the very base of the ventral canal, so that there 

 are no well-defined transpiratory and assimilatory surfaces. The epidermal cells are 

 uniseriate, with rectangular or conical cavities, the hypodermal cells extending round 

 each leaf to the base of the ventral canal of the collateral leaves, where the cuticle 

 is marked by elongated processes as in Callitris. Here also the palisade parenchyma 

 is much more closely packed than on the dorsal side, the material of the spongy 

 tissue being particularly loosely distributed or attenuated, and connecting the 

 former with the sparsely scattered parenchymatous cells, as well as the strengthen.. 

 ing walls of the oil cavities. The central cylinder of bundles of the branchlet is 

 surrounded by transfusion tissue more marked than in the Callitris ; each leaf 

 has an individual bundle normally orientated, backed on the outer side witn 

 parenchymatous endodermal cells. (Figures 205-206.; 



(c) Chemistry of the Leaf Oil. 



This material was received from the Government of Western Australia' 

 and was distilled 6th July, 1903. It consisted of the leaves with terminal branchlets 



