BY A. A. HAMILTON. 159 



detail, in the carefully executed plate by Miss M. Flockton, 

 illustrating this species. A series of leaves of Dodonoia tri- 

 quetra Wendl., showing a considerable range of variation within 

 this species, was exhibited before this Society(13; 1915, p. 628). 



LEGUMINOSiE. 



In this Order, the genus Acacia has presented many problems 

 in leaf-variation to the systematist, the exceptionally wide range 

 of habitat of many species of the genus necessitating consider- 

 able alterations in the structure of the foliage, to meet the re- 

 quirements of the varied environmental conditions encountered 

 within the sphere of their acr.ivities. An example of this 

 elasticity is found in the alteration of the texture of its phyllodes, 

 by A. suaveole7is Willd., during its passage from the lower to the 

 liigher elevations on the Blue Mountains(12; 1915, p. 389) In a 

 footnote to his description of A rustelli/era, Bentham, (*; ii , 

 p. 368) who has reduced A. subbinervia Meissn., to a synonym of 

 his species, writes— "The second nerve of the phyllodia, from 

 whence Meissner derived his name, very seldom occurs, and was 

 therefore in some measure exceptional in the specimen described 

 by him." Discussing the .4. (fec?<.n*e?is Willd., group of "Wattles," 

 Mr. J. H. Maiden(19; iii., p 40) draws attention to the following 

 points : — The pinnules of all vary more or less in each variety in 



length, breadth, and insertion A decurrence of leaf-stalks 



is common to all The indumentum is variable The 



number of glands varies in each variety in the same tree. 

 Further remarks by the author accentuate the wide range of 

 variation within this group. Under /I immila Maiden tt Baker, 

 (20; p. 87) is the following note by Messrs. Maiden &, Betche : — 

 "Since publication of this species, many additional localities 

 have been discovered and the additional material necessi- 

 tates some modification of the description. The phyllodia are 

 described as G lines long and 1 line broad; it should read instead, 

 phyllodia from i to nearly H inches long, 1 line broad in the 

 short-leaved forms, considerably narrower in the long-leaved 

 specimens." Mr. R. H. Cambage, F.L.S.,15) illustrates some of 

 the difficulties in discriminating between several members of this 



