280 



at a little distauce, the tree appears to liave a composite truiil': willi two kinds of bark, 

 and to have two kinds of foliage,, as represented by two large branches of the different 

 species concerned. 



There is a fine example of this inarching of branches, 12 inches in diameter, in 

 E. hcemastoma var. 'inicmntha in the Federal Territory, on the Queaubeyan-Uriarra 

 road, near the saddle of Mount Stromlo. Mr. C. J. Weston pointed me out the tree 

 and sent the photograph (February, 1920), which will be subsequently reproduced. 



There is another illustration of cohesion of branches in the figure of E. rostrata 

 by A. D. liardy, Plato XL Proc. Roy. Soc. Yid., xxix (Xew Series), 167 (1916). 



'■ An excellent instance of fusion of shoots (post-genital) was observed in the 

 ca.se of E. sahnonopJiloia: two cross-bars occuiTed, one close above the other; a very 

 rare case."' (" Principles Plant Teratology,"' Worsdell. i, US). 



It will be observed that all the Eucalypts quoted are Gums, or, if rough barked 

 on the trunk, with smooth branches. In an allied genus, Anyophora. A. lanceolata is 

 perhaps the commonest tree in Eastern Australia to show the phenomenon, and that 

 is a smooth bark also. In the case of the rough barks, it is fair to suppose that the fusion 

 took place at an early stage of the plant's history, before the rough bark had developed. 



■' Naturally grafted branches are fairly conmion on Beech. r)ak. Holly, Lime, 

 Willow, Yew, and Scots' Pine, whdst they mav also be noted on many other trees." 

 (" Xatural Grafting .of branches and roots," by W. DalUmore, Keir Bulletin, 1917, 

 p. 303). Mr. Dallimore discusses the way in which this grafting has been brought 

 about in certain cases. Speaking of the friction between two branches, caused by the 

 wind, he points out that a good deal of tissue may be destroyed, and aU the time 

 nature is trying to repair the injury by forming patches of callus on both branches, 

 at those places where friction is least active. As the branches become heavier and 

 movement ceases, the patches of callus grow together, and eventually a strong union 

 is effected between the two branches. The paper is suggestive, and should be referred to. 



2. Adhesion of Branches. 



lender Cohesion of Branches,"' at p. 279. I have quoted a paper from my pen, 

 and it will l)e seen that the Xatural Grafts there enumerated are vastly more 

 numerous in the case of Adhesion, i.e., where two different species (and more rarely, 

 genera) are concerned. I will content myself with a few supplementary notes. 



Following is a relatively early reference to natural grafts. '" If nature does 

 not admi:: of crossing in the genus Eucalyptus, it certainly encourages that of grafting, 

 for, in the neighbourhood of Mudgee, the Apple {Angophom intermedia) may be grafted 

 naturally on E. rostrata, whilst, on the Richmond Common a similar eccentricity may 

 be seen on E. tereticornis." (Rev. Dr. Woods in Proc. Linn. Soc. N.S.W., xvi, 61, 1891.) 

 I have not seen the reputed Mudgee graft, but that on the Richmond Common was a 

 false graft, in other words, no graft at all. See my " Forest Flora of Xew South Wales," 

 Vol. vi, ]i. 79. 



