177 



AFFINITIES. 



1. With E. coceifera, Hook., f. 



The variety elata is very close to E. coceifera. It is often very difficult to 

 separate them on herbarium specimens alone if ripe buds are not available, those of 

 E. coceifera being more or less corrugated. 



2. "With E. amygdalina, Labill. 



The affinity of E. amygdalina to E. Risdoni is undoubtedly close, the 

 relationship being closest through the var. elata of the latter. E. Risdoni has 

 broad sucker leaves, and on this character alone I would retain it as a species separate 

 from E. amygdalina. 



The bark of E. Risdoni is smooth ; that of E. amygdalina is always fibrous * 

 on the butt ; this is an important character. 



In these days the determinations of Eucalypts by the older botanists are 

 carefully criticised, in view of the extensive field knowledge of the genus we now 

 possess, and which is becoming increasingly accurate, but the following remarks by 

 Bentham (B.F1. hi, 203) seem to be quite accurate : — 



F. Mueller also unites E. Ris loni altogether with E. amygdalina. J. D. Hooker and Oldfield, both 

 of them from observations made on the spot, have assured me that the two are quite distinct, in habit as well 

 as in the bark. The sessile opposite leaves occupy frequently the flowering branches of E. Risdow, and are 

 only on the saplings and adventitious flowerless branches of E. amvgdalina; they are, moreover, broad, 

 frequently connate, and usually glaucous or nearly white in the former ; always, as far as known, narrow- 

 ovate or oblong-lanceolate in E. amygdalina. When the leaves are alternate, they appear to be broader in 

 E. Risdoni than in E. amygdalina, the pedicels thicker and more angular, the flowers and fruits larger — 

 differences, however, of degree only, to which our dried specimens do not admit of our fixing any precise 

 limits, and in that state it is sometimes scarcely possible to decide to which species they should be referred. 



3. With E. obliqua, L'Herit. 



I propose to inquire into the position of a " Gum-top Stringy bark "f called 

 also, at least in New South Wales, " Mountain Ash." 



The following botanical names for it are synonyms : — 



1 . Eucalyptus obliqua, L'Herit., var. alpina. Maiden (JProc. Just. Assoc. 



Adv. Science, Vol. ix, 369, foot-note.) 



2. E. gigantea, Hook., f., El. Tas. as regards Plate xxviii ; also, as regards part 



of the text. 



3. E. radiata, Hook., f., El. Tas. i, 137 (non. Sieb.), var. 4 (partim). 



4. E. delegatensis, R. T. Baker, Proc. Linn. Soc, N.S.W., 1900, p. 305. 



* Mr. Rodway writes to me : — " Many forms of undoubted E. amygdalina are smoth-barked from the butt.'' 

 Nevertheless, in view of the uncertain position of E. linearis, I prefer to leave my remarks on the bark to stand for the 

 present. 



t See Part II, p. 68 of this work. 

 E 



