PRESIDENT'S ADDRESS. 45 



lamina aud a normal leaf -stalk. As successive leaves are formed, the leaf -stalk 

 gi-aduaUy broadens, whilst the lamina is reduced until the form of the phyllodg 

 is attained, in some species foliage-leaves may again appear after the phyUodes, 

 for instance in A. heterophylla." 



Also, in Vol. ii., p. 355 he adds — "The best examples of the formation of phyl- 

 lodes are to be found in a number of Australian species of Acacia." It is usually 

 said that in the phyllode of Acacia the lamina is entirely wanting. This is incor- 

 rect, for the lamina can always be seen upon the priniordium. ... In some 

 species, for example A. floribunda, A. melanoxylon, and A. unoinata, there are 

 transition-forms which show that the rhachis may have a share in the formation 

 of the phyllode." 



Inadequate material, and the disregard of the presence, the meaning, and the 

 significance of the terminal seta, as in so many other cases, are herein responsible 

 for the misinterpretation of seedlings. What Goebel calls the primordium of the 

 lamina, which is always present upon the phyllode, I should term the terminal 

 seta merely, or sometimes, in the young or early euphyllodes (but not in late ones), 

 juvenile stages of a pair of pinnae, always the apical pair, together with the ter- 

 minal seta, at the apex of the flattened common petiole. His suspicion that, in 

 some species, the so-called phyUodes are something more than flattened leaf -stalks, 

 is interesting. I regret that I have not been able to make more use of Goebel's 

 important treatise. I have been unable to purchase or borrow it; and there are 

 so few copies in Sydney, that one can consiilt them only under time-consuming 

 conditions. 



EXPLANATION OF PLATES i.-viii. 



KEFEEENCE LETTERS. 



a. i. p., leafless, thread-like axis of the terminal pinna-^. t. 5., foliaceous ter- 

 minal seta — /. />., terminal pinna — t. s., terminal seta 



Plate i. — A. suaveolejis (reversion-foliage). 



Figs. 1-7 and 11 show leaves with two pairs or one pair of good pinnae on the 

 •upper part of the common petiole or primary leaf -axis; and poorer pinnse with a 

 reduced number of leaflets, or a pair of leaflets or odd leaflets on the margin of the 

 lower part of the flattening leaf-axis below the second good pair (when there are 

 two pairs), that is, on the developing half-euphyllode (the flattening on the upper 

 side of the axis only), or euphyllode. Note the inversely proportional ratio in 

 which the two antagonists are present. 



Figs. 2 and 6 show also three leaves at a node, the two lateral ones simply 

 pinnate. 



Figs. 4, 7, 9, 10 show green, foliaceous, terminal setae. 



Plate ii — A. implexa (?). 



Fig- 1 — An average complete euphyllode. 



Fig. 2. — K seedling showing the transition from a bipinnate leaf with one pair 

 of pinnae (the apical pairl to a complete euphyllode on the fifth leaf. The fourth 

 leaf is a portrait of the two juvenile antagonists — a pair of pinnae (bantam), and 

 the leaf-axis or common petiole to which they are attached (the potential heavy- 

 weight, which, after the tussle is all over, attains the dimensions of the example 

 shown in Fig- 1) . 



