336 



Mr. II. G. Smith has made a chemical research in the matter " On the elastic 



substance occurring on the shoots and young loaves of Eucalyptus corymbosa and some 



speeies of Angophora." [Proc. Boy. Soc. N.S.W. xlii. 133. 1908.) The result of this 



investigation showed this elastic substance to be 'identical in composition with 



ordinary india-rubber, and that it is eventually oxidised to a white powder. A 



vegetable wax was also isolated at the same time. 



If Eucalyptus caoutchouc could be obtained in quantity il seems reasonable to suppose thai it. 

 would bavc considerable commercial value. Tin- small percentage amount) bowevcr. makes it at present 

 i'( scientific value only, without taking into consideration the diHiculty of collection, its rapid change, and 

 that it only occurs at certain times of t he year. 



Anatomy. 



This has been referred to to a. very brief extent at Part J. pp. 7, 8. There will 

 lie a reference to Mr. W. B. Welch's papers on leaf-anatomy in Part LV1I. 

 Following is a very old anatomical reference : — 



These two genera (Eucalyptus and Acacia) still more uniformly agree in the similarity of the 

 opposite surfaces of their leaves. But this similarity is the indication of a more important fact — namely, 

 the :• ially on ')oth surfaces of the leaf of those organs, for which, as I believe them to be in 



general imperforated. 1 have adopted the name of cutaneous glands, but which by most authors are 

 denominated pores, or slomata of (lie epidermis. (1!. Brown in Ji urn. Roy. Gcog. Soc. i, 21, 1832; in his 

 Coll. 'Works, i. 311.) 



The stomata in leaves as a rule are chiefly, or wholly, to lie found on the 

 concave side, beneath which lies the soft green tissue with its ramifying air-passages. 



With reference to Mueller's notes in " Eucalyptographia," already referred to 

 at Part I. p. 8, of the present work, he has the following references to stomata in the 

 same work :— 



1. Lists of measurements of numbers on. leaves of various species, under — 



(a) E . pachyphylla. 



(b) E. plioenicea. 



(c) E. macrorrhyncha, i2 l-t times mag. (Figure 1 of the Supplementary Plate)- 

 ((/) E. rostrata (Figure I. of the Supplementary Plate). 



{(') Figure on. E. Sieberianu plate. 



2. Drawings of cuticle (x 450) of 20 species, under E. microtheca (Supplementary 



Plate). 



A'. Abergiana. E. ma/rginata. 



E. til pi an. E. microcorys. 



E. botryoides. E . microtheca. 



/•.'. buprestium. E . peltata. 



E . clavigera. E . RarviHianu. 



/-'. Cloeziana. E. rest it if era. 



E . ij/obii/iis. E . sdnsit. 



E . iji)iiip/iocrj)/in/u. E ". sid&tophloia. 



E. incrassata. E . tetrodonta. 



E. Ini-i/ifloi-i'iis (bicu/or). E. Torclliitiiu. 



