276 



The position of the stomata is wortliy of notice in this case, as well as the 

 general absence of decurrent channels — a condition of circiunstances probably 

 due to natural selection or adaptation to environment and, perhaps, produced 

 by the climatic conditions of the island home of this species, for the West Coast 

 of Tasmania is notorious for its great rainfall. This disposition of transpiratory 

 organs is in marked contrast to what realises \vitli the Callitris of the arid interior 

 of the continent, where all have marked decurrent channels into which the stomata 

 communicate, and by which they are well protected from the heat, and other 

 adverse climatic conditions. Figure igo illustrates a section cut well down the 

 internode of a branchlet, and showing no oil reservoirs. Figure igi is a 

 cross-cut higher up than Figure igo, and takes in the lower extremities of the 

 oil ca\at\- in each leaf, whilst in Figure ig2 the triangular shape of this 

 section is complete, and being cut through the middle of the oil cavities shows 

 the varving diameter of these bodies compared with those given under Figure igi. 

 The parenchvmatous cells are arranged in a fairly regular manner around the 

 central axis and oil reservoirs, and may almost be called quite endodermal in this 

 instance. It will be noticed that they are all empty. The leaf trace can be seen 

 but not the transfusion tissue, which, in this species, is only developed to a limited 

 degree. Figure ig3 is a longitudinal section cut through the centre of a branchlet 

 and offshoot. 



(c) Chemistry of the Leaf Oil. 



This material was collected at Avoca, Tasmania, 25th June, igo8. The 

 leaves and branchlets, containing some fruits, were taken for distillation, and this 

 was continued for six hours, but the yield of oil was very small, as 526 lb. of 

 branchlets only gave 4^ oz. of oil, equal to 0-054 per cent. The crude oil was 

 somewhat dark coloured, but after agitation with a dilute solution of soda it became 

 of a light-lemon colour. It was very mobile, and had an odour somewhat resem- 

 bling Callitris oils generally, but, perhaps, more aromatic than those of the 

 C. glauca group. The esters were in somewhat small amount, and appeared to 

 consist mostly of geranyl-acetate, as only a small amount of bornyl-acetate could 

 be detected. In this respect the oil belongs more to the group to which C. calcarata 

 is a representative than to that including C. glauca. The principal terpene present 

 in the oil of this species is pinene, the dextro-rotatory form being the most pro- 

 nounced, and no less than 80 per cent, of tlie crude oil distilled below 170° C. 

 The limonenes were present, but only in a very small amount. Tlierc was also 

 detected a small proportion of a high boiling constituent other than the esters, 

 and which was most probably a sesquiterpene or similar body. This was 

 indicated by the distillation results, the refractive index, and the specific 

 gravity of the crude oil. The oil, consisting mostly of j^inene, was naturally 

 somewhat insoluble, and it difl not form a clear solution witli m xolunns ol 



