i8 



It will be noticed that an attempt has been made to associate the morphology 

 and histology of the leaf with the chemical constituents of the oil occurring in 

 the respective oil cavities of the different species. Owing to the leaves being so 

 small, and the absence of veins on their surfaces, this held of observation was 

 wanting, and it was further found that no help was gi\-en by the disposition of 

 the leaf bimdles, as indicating the characteristic chemical constituents of the oil, 

 as was shown by us to obtain in the genus Eucalyptus. Botanical instances of 

 agreement with the oil had therefore to be looked for in another direction, and 

 by studying the anatomical structure it was found, in the material examined by 

 us, that the species divided themselves fairly well, both botanically and chemically, 

 into groups, according as certain recognised bodies that generally go to make up 

 leaf substance were absent, present, or in abundance in the leaf tissue. Thus, 

 those species hax-ing abundant transfusion tissue, and little or no sclerenchy- 

 matous or stone cells in the leaf substance, had the predominant limonene in 

 the leaf oils in the dextro-rotatory form. This group included — 



C. robusta. 

 C. verrucosa. 

 C. propinqiia. 

 C. glanca. 

 C. arcnosa. 



The next class includes — 



C. intratropica. 

 C. gracilis. 

 C. calcarata. 

 C. rhomboidea. 

 C. Tasmanica, 



in which the transfusion tissue is less developed, or the cells not so numerous, 

 while the sclerenchymatous or stone cells gradually begin to appear amongst the 

 parenchymatous tissue, in a small cluster between the phloem of the leaf trace 

 and the oil cavities of the first group, and then gradually increase in number in 

 the succeeding species, where they are conspicuous figures in the spongy portion of 

 the mesophyll. and reach their maximum in C. rhomboidea. In this class the 

 predominant limonene in the leaf oil is la^vo-rotatory. 



In the rcnianimg species — 

 C. Drummondii, 

 (C. Roei), 

 (C. Morrisoni), 

 C. oblonga, 

 C. Muelleri, 

 C. Macleayana, 



