NOTES ON EUCALYPTUS. 321 



3. A similar specimen from E. J. Dunn, Pine Greek 

 Railway, same date, also in bud and leaf. 



4. Specimen in leaf, bud and flower from Pine Creek, 

 J. H. Niemann, August, 1904. This differs from the type, 

 and Nos. 2 and 3, in having distinct pedicels to the flowers. 

 There is a slight umbo to the operculum, probably because 

 the bud is fully developed. The leaves are mostly narrower- 

 lanceolate than the type, and most have distinct, though 

 very short, petioles. 



Affinities. 

 This is another of the few species which flower in the 

 opposite-leaved or juvenile stage. 1 If described from the 

 type only, it might have been looked upon as a homoblastic 

 species, but the additional material I have quoted shows 

 that, like E. praecox (loc. cit.) it is heteroblastic, like the 

 vast majority of species of this genus. We can only say 

 that it is an example of retarded heteroblasty. 



Other instances of retarded heteroblasty in Eucalyptus 



are 



E. Risdoni, Hook. f. See Plate 32 of my "Critical 



Revision of the Genus Eucalyptus." 



E. Glllii, Maiden. See Plate 67, op. cit. 



E. cinerea, F.v.M. See Plate 89, op. cit. 



E. cinerea, F.v.M. var. multiflora. Plate 90, op. cit. 



E. melanophloia, F.v.M. 



In the absence of a complete suite of specimens and full 

 data as regards E. Houseana, I am only able to suggest 

 relationships to the following species at present. 



1. With E. alba, Reinw. The flower-buds of E. Houseana 

 may resemble those of E. alba a good deal. Exceptionally 

 the leaf-blade may resemble that of E. Houseana in shape 

 and venation, but that of E. alba is not sessile at any stage, 

 not cordate at the base, and is often gross in size. Speaking 



1 Compare, this Journal, xlviii, 424, (1914). 

 U— November 3, 1915. 



