204 



2. Hand-crushing of Leaves for Discrimination of Species. 



As long as I can remember anything in Eucalyptus study, both in the bush and 

 in the herbarium, I have been in the habit of crushing leaves and endeavouring to 

 recognise them by odours. A few notes of the kind will be found scattered throughout 

 this work. What diagnostic value will ultimately be found in these observations I do 

 not know, but they are quite worthy of being followed up, primarily in the interests 

 of field botanists. 



For example, there is an indefinable, soft, pleasant, fragrance (does it remind 

 one of apples ?) in E. coriacea, E. de Beuzevillei, E. coccifera, E. altior, E. gigantea, 

 E. Risdoni var. elata, E. viminalis, perhaps augmented by an attenuated atmosphere, 

 just as E. radiata and E. dives, for example, fill the countryside with a peppermint 

 odour on a misty day. In 1902 I recorded that E. linearis sometimes has a faint odour 

 of oil of geranium when crushed. On 18th February, 1918, Mr. Blakely informed me 

 that young shoots of E. eximia in the Hornsby-Galston district (a few miles north of 

 Sydney) distinctly smell of oil of lemon. 



There is evidence of a tendency to uniformity in the chemical composition of 

 oils in a few species, and further inquiries will doubtless be made in the future. Following 

 are examples : — 



' The oils of E. oleosa and E. salmonophloia consist of the same constituents, 

 and, allowing for rather more pinene in the oil of E. salmonophloia, practically no 

 difference could be determined between the oils of these two species . . ." (H. G. 

 Smith in Proc. Linn. Soc, N.S.W., XXXIX, 26, 1914.) 



The oils of two species from Kangaroo Island (E. cneorifolia and E. odorata) 

 are almost identical in composition with that yielded by E. polybractea (fruticetorum), 

 (H. G. Smith in Trans. Roy. Soc, S.A., XL, 467, 1916.) 



3. Angles of Secondary Veins with Midrib. 



In the following species one or two typical leaves were selected by Mr. R. H. 

 Anderson from a number of herbarium specimens, and two average angles measured 

 in the middle section of each leaf. (See Part LVII, p. 394.) The number of angles 

 falling under a given angle are tabulated, thus showing the general range of venation 

 angles. It will be seen, from the evidence submitted, that the majority of angles of 

 one species lie within a range of about 10 degrees, 



