233 



5. Mudkr, 1879-84.— Mueller " Euealyptographia," 1879-84, in defining the 

 genus, speaks of the leaves "' of very young states of the plant frequently different in 

 texture, position and shape to those of the more aged plants . . ." 



He seemed to avoid a term for the description of young leaves. In the generic 

 description he speaks of those " of very young states." 



At the same time he figured the young foliage of the following twenty species, 

 although he did not name the young state in the description of each plate. He did 

 not use this state for diagnostic purposes : — 



E. amygdalina. E. obliqua. 



E. calopliylla. E. pauciflora (coriacea). 



E. diversicolor. E. piltdaris. 



E. eugenioides. E. piperita. 



E. Foelschiana. P. ptychocarpa. 



E. globulus. E. redunca (? accedens). 



E. goniocalyx (?). E. rudis. 



E. leucoxylon. E. salmonophloia. 



E. macrorrhyncha. E. Stuartiana. 



E. melliodora. E. viminalis. 



6. Xaudin, 1883.— Naudin, both in his 1st Mem. (1883) and 2nd Mem. (1891) 

 drew attention to the young foliage in a manner clearer than had previously been done. 

 Although his classification is mainly based on the fruit, it will be observed that he calls 

 in the aid of leaf-contrast (uniform and biform). 



He employs the amount of variation in Eucalypts as regards the juvenile and 

 mature foliage to constitute two series — 



(1) Biform (Especes bifonnes). 



(2) Uniform (Especes uniformes) (ii, 9). 



He has been speaking of the Cotyledons, and he goes on to say (Mem. i, 347) 

 of which the following is a translation : — 



The variations are much greater in the following period, and it is there, indeed, that the difficulties 

 of specific diagnosis begin. The first leaves which follow the cotyledons are seldom the shape of those 

 which appear at a later period. They are sometimes alternate and petiolate from the start; more often 



or almost sessile; but while in most species this last characteristic only 

 affects the 6 or 8 first leaves, in other species also in great number, they remain sessile and opposite during 

 a long period of the youth of the tree, aud sometimes during its whole life. (A note follows which will 

 be found at p. 314 under Connate Leaves.) 



There are. as we have seen, some Eucalypts which are really biform ; that is to say, in which the 

 juvenile stage so little resembles the adult, that it would be impossible to connect the two stages to the 

 same species, if one had not been present at the passage of the one to the other. Habitually in the case of 

 Eticalypts with opposed and sessile leaves at an early stage, the adult phase is characterised by leaves 

 alt'-rnate, petiolate, more or less long-lanceolate, nearly always arranged on an oblique plan and vertical 

 relative!',- to the horizon, caused by semi-torsion of the petiole. In this state many species resemble one 

 another, and if we had no other resource than the leaves, it would be often impossible to distinguish one 

 species from the other An interesting fact to note, is that if the stems of these adult trees are cut down to 



