-'54 

 It is differentiated from cognate species bv— 



1. Its fruits which have almost equal valves and which are thicker than 



those of other fruits of equal size, and the base of the cone also 

 tapers into the peduncle. 



2. Its comparati\ely large decurrent leaves, which give herbarium material 



a coarser appearance than the others. 



3. Its anatomical characters. 



4. Its chemical constituents. 



III. LEAVES. 

 (a) Economic {vide Chemistry). 

 (V Anatomy. 



These leaves are characterised by their angularity and a cross-section 

 through a branchlet and the three decurrent leaves form a ver}' fair equilateral 

 triangle, whilst an examination of the leaf tissue reveals a certain specific structure, 

 as, for instance, the occurrence of hypodermal cells at the ventral surfaces of the 

 leaves — a feature found not to occur in any other species. The occurrence of a 

 comparatively large number of branched sclerench\matous ceUs in the fundamental 

 tissue is only paralleled in the leaves of C. rhomboidea, whilst the disposition of 

 the transpiratory surfaces is identical with those of the Tasmanian species, 

 which circumstance calls for investigation into the enxironment of these two 

 species, C. Drummondii and C . Tasmanica. 



In Figure 176 the oil cavities of each individual leaf form a conspicuous 

 object, whilst at the most acute angle of the triangle the double row of hypodermal 

 cells can be seen, and at the base or ventral surface can just be made out similar 

 cells, with their long axis running obliquely to the surface ; this is more distinctly 

 shown in all the other figures gi^•en urrder this species. The branched sclerenchy- 

 matous cells in the mesophyll are shown cut at different angles, whilst the number 

 of parenchymatous cells and transfusion tissue is very limited in this species ; some 

 of the former are, however, occasionally found filled with the brow^n content, — the 

 manganese compound. The assimilatory surfaces of the leaf are at the apex and 

 free base portion, the transpiratory area lying between these two, so that the 

 palisade parenchyma does not present so solid a phalanx as generally obtains in 

 Callitris leaves. Figure 177 show-s two of the three lea\es with oil ca\ities, 

 but generally each possesses an oil reservoir; the sclerenchymatous cells show out 

 prominently. Figure 179 being cut well below the node has no oil cavities in 

 the leaves. 



