120 Kelly, Concerning Acacia Phyllodes. rvIi"^*xxYx. 



face with one of the most difficult problems of heredity. Would 

 these acquired characters persist ? They have done so. By 

 this time climatic changes, more or less, may have come about 

 throughout the island continent. The adaptation may have 

 been as suitable in any district as the normal condition. The 

 acquired character may have become so well fixed as to pass 

 by inheritance ; or, as all organic nature has in itself, dormant 

 or active, the highest capacities of its kind, each species would 

 have the power to continually adapt itself to circumstances 

 and to retain either its adopted form or revert as conditions 

 necessitated — be the way weary and the process slow. Thus 

 all species of acacias were at one time merely endemic varieties, 

 and are still subject to change. Note how they fluctuate in 

 cultivation or in sporadic growth. See how, even in their 

 apparent homes, the phyllodes vary even on one tree in size, 

 in shape, in texture. They conform to no standard ; they are 

 undrilled, undisciplined ; they struggle still for uniformity and 

 the dead level of the orthodox. 



Measurements of the phyllodes of many plants taken show 

 a great variability in size even on the same bough, to say nothing 

 of those on the same tree. On one branch phyllodia of A. 

 pycnaniha varied from 84 lines x 33 to 95 x 7 ; on /I. melan- 

 oxylon (Blackwood), from 50 x 18 to 35 x 8 ; on ^. penninervis, 

 from 72 X 24 to 51 X 8 ; on A. leprosa, from 4 in. x | in. to 

 i^ in. X |, and in cultivated species to ahnost linear; on A. 

 saligiia, from 108 x 3 to 108 x 7 ; on A. iii'earis, from 7 in. x 

 I to 3J X I to 9J X ^ ; on A. diffusa, from ij in. x ^^ to ^ in. x 

 TTo inch. 



The acacias, in common with other life, possess the jiower 

 of achieving the limit of j^erfection, and this ])articular genus 

 truly according to its light. They are exercising this jwwer 

 in a revolutionary way. They do not intend to be, as to their 

 lea\'cs, outside of conventional rules. Circumstances robbed 

 them of their leaves and gave them deformities, llattened leaf- 

 stalks, and really, in some cases, dilated midrilis. The midrib 

 or the petiole, as the case may be, has split uj) and expanded 

 like a fan or web foot, always more rather tliau less con- 

 stricted, carrying the leaf tissue as the web instead of allowing 

 it to grow in its ordinary manner, as though it had forgotten. 

 In Acacia acradenia the veins or ribs diverge from one thickened 

 edge or leaf-stalk, and are like a half leaf, that edge taking the 

 ]ilacc of a midrib. Professor Rali)h Tate, in describing A. 

 lysiphloia, a Finke River sjjecies, refers to the " leaves." 

 Mueller, in his "Iconography," calls them " phvllodes." The 

 inference is that Tate considered the j^hyllodes of this species 

 had completed the cycle. The ])hyllodes ol .1. niieiira \'ary 

 from cylindrical to (lat. In .1. latijalia the ner\es branch off 



