2SS 



structure (my italics, J.H.M.), whatever may be the part of the tree from which they have arisen. 1 saw- 

 also at Cannes many old Eucalypts that had been entirely robbed of all their branches, and whose trunks 

 thns mutilated bore, on their tops, ;ln abundant head of adventitious shoots presenting all the juvenile 

 characters, Having written on this subject to the late M. Naudin, then Director of the Villa Thuret, and 

 who had made, as is known, a special study of Eucalypts, I received the following reply from him which 

 will not be read, 1 think, without interest : •' 1 am pleased to he able to confirm your observation on 

 Every lime that this trie has its trunk cut. it produces an abundant tuft of shoots, 

 which has completely returned to the juvenile state: large leaves, opposite, sessile, or almost so. whitish 

 grey, and with a balsamic and penetrating odour: quite different, in a word, from those of the adult tree, 

 which are alternate, falcate, petiolate. with whitish powder, and little or not at all odorous, at least on 

 being crushed between the tinkers. And note that it is nut only at the base of the tree, but at all heights 

 of the trunk, wherever one cuts it that this transformation takes place. Even the simple removal ofa 

 slightly heavy branch is the starting of a number of branches returned to the juvenile stage. 1 have 

 observed the sane- thing on Ewcdypl alis, which is very ' Inform." See p. 285). Loppings cause 



the appearance of bunches of branches in the juvenile stage. Jt seems probable to me that the same 

 modifications would be observed on all the thoroughly ' biforni' Eucalypts. It would be less evident on 

 the ■ uniform' ones. 1 think 1 have also seen similar changes in appearance or something the same on 

 other trees." 



13. Musson, 1905. 

 The large size of many of the sucker and seedling leaves, as in our Cabbage Gum (E. hwmastoma), 



with their frequent horizontal position, doubtless points to necessary "protection" afforded to the 

 young growing tree, possibly a ""throw-back" to leaf character at a time when the Gum Trees 

 lived under more favourable conditions lure as to rain and sun — to a. great rainfall period, when 

 huge marsupials roamed our forests, and much of Central Australia was occupied by sea: when sun heat 

 was less, sand evaporation much less than at present take-; place. With such surroundings leaf growth 

 would be larger, leaves would hang horizontally, and there would be no necessity fur narrow, drooping 

 leaves. Presenl variations therefore lead to interesting speculations in this direction ("' Hawkesbury 

 Agricultural College Journal." N.S.W., 25th March. 1905 p. 68). 



11. Diels ni"l Pritzel, 190.3. — These authors, e.g., Engler's But. Jahrb. xxxv, 438 

 (1905), iis«' the words " fohusprimariis." Diels. in his 1 ' Jugendformen mid Blutenreife " 

 m1 t lie following yen-, usually speaks of " Jugendform " as applied to Eucalyptus foliage. 



1.5. f7/„,/x/r/r. 1913. 



" Juvenile leaves. Under the designation "i juvenile leases may be included not <<t>i<i 



seedling leaves, but also most "I iJiosi of certain adventitious growtlis (my italics, J.H.M.) abundantly 



produced by cutting or wounding parts of the barrel or branches, and which in Australia are 



popularly known as sucker . and the difference between these leaves and the mature or adult foliage of the 



sain- i ii n -■> greal as to convey the impression n who has not studied the genus that they 



belong to distinct species. It is remarkable that Eucalypts rarely, if ever, produce true botanical suckers 

 or shoots from thi roots, and a careful examination of the young grow ths which appear around and at some 



little distance fr a standing tree and look like true suckers, results in the discovery that the plants ate 



seedlings. 



Between ten bool end seedling leaves there is a great similarity and as according to the 



general biological belief it is in the young forms of both flora and fauna that we may expect to find the 

 greatest resemblance to ancestral types -" we may regard these reversion shunt- a- ol almost equal value 

 with the seedlings for the purpose of studying the ancestral bums of Eucalypts. Although the leaves of 

 these '"suckers" when available are of considerable assistance in the identification of many species, they 

 vary within certain hunt- both iii i/e end shape, possibly in response to differences of climate, and to 

 nies uf nourishment and poverty. An interesting feature of their form is the degree of dissimilarity 

 between them and tie- mature leaves. In some instances (he different is slight uml in others exceedingly 

 greal. Mr. Andrews lias already pointed out that the difference is greatest in tin- highland and coastal 

 •n {.limn*. Roy. Soc. N.S.W., xliv. 167, 1910). (R. II. Cambage in same ./<>"/>. xlvii, l'jl-"..) 



