103 



2. With E. Caleyi, Maiden. See Part XII of this work. 



Twigs of the two species are often a good deal alike. The juvenile leaves of 

 E. Caleyi are much more orbicular, the flower buds of E. affinis are more angular, 

 and in E. Caleyi have an egg-in-egg-cup appearance. Typical E. Caleyi is an 

 Ironbark, but (Part XII, p. 97) it may have bark of a more boxy nature. Both 

 are normally glaucous. The anthers of E. Caleyi are more pronouncedly terminal. 



3 and 4. With E. sideroxylon, A. Cunn., and E. hemiphloia, P.v.M., var. 

 albens, P.v.M. 



Messrs. Dearie and Maiden, at the publication (1900) of E. affinis, wrote : — 



The true affinities of our species are, in our opinion, with E. sideroxylon, A. Cunn., and 

 E. hemiphloia, F.v.M. Roughly speaking, it resembles the inflorescence of E. hemiphloia, the fruits of 

 E. sideroxylon, while its timber and bark partake of the characters of both. 



Mr. Cambage is of opinion that the tree is a hybrid between E. hemiphloia, var. albens, and 

 E. sideroxylon, a view which had already occurred to us. It certainly seems only to be found when the 

 other two trees are present. There are difficulties in the way of recognising hybridism in Eucalypts, and 

 as we propose to treat this subject later on we refrain from being dogmatic on the present occasion. 



Below we give an account of some trees which partake of the characters of both an Ironbark, 

 probably in this case E. siderophloia, and a Box, E. hemiphloia, and here hybridism again suggests itself. 

 (E. Boormani is referred to. — J.H.M.) It is curious that in E. affinis we have a tree also partaking of 

 the characters of an Ironbark and a Box, but in this case E. sideroxylon and E. hemiphloia var. albens, 

 apparently combine. 



In view of the imperfect evidence of hybridisation before us we think it safer to give to E. affinis 

 specific rank. 



I wrote (Proc. Linn. Soc. N.S. W., xxx, 498 [1905]) :— 



In that paper some doubt was expressed as to the hybrid origin of E. affinis. I desire to say that 

 I have now no doubt as to its hybrid origin. Others and myself have found ic growing over large areas of 

 country with E. sideroxylon and E. hemiphloia var. albens. The tree certainly is an intermediate between 

 this species and variety, and I look upon these trees as its parents. 



In accordance with the promise made in an earlier page of this work, I shall 

 deal specially with the subject of hybridism in this genus. I intend to devote one 

 or more Parts to the necessary illustrations. 



