BY J. J. FLETCHER AND C. T. MUSSON. 195 



tissue through some injury, or possibly at the point where the 

 cotyledons of sucli seeds as those of the stone-fruits are attached 

 to the young plant. In Eucalyptus seedlings, the natural knots 

 often appear opposite each other where the cotyledons have pre- 

 viously been attached, also the quince knots appear first at the 

 node about the old leaf-scar. All the evidence we have, goes to 

 show that some injury or weakness is necessary for infection to 

 take place.'' 



[Legend of Text-fig.21, p.549].— "Artificially caused galls on 

 forest red gum \^Eucalyptus tereticornis]. Crown Gall has not 

 been known to attack the various species of Eucalyptus in nature. 

 The significance of swellings found frequently at the crown of 

 young gum trees is not yet understood. They do not appear to 

 be detrimental to the tree. " 



Victoria Bottle Tree {Stercnlia diversifolia) [tig.20], and Flame 

 Tree {S. acerifolia) were successfully inoculated (p. 552). 



"Forest Red Gum {E. tereticornis) [fig.21]. — Seedlings of from 

 four to six feet were inoculated. The first successful inocula- 

 tions were made May 16, 1910. On March 25, 1912, there was 

 one large knot and one very small one at points of inoculation. 

 September 2, 1911, inoculated a seedling about one half inch in 

 diameter. February 20, 1912, there were two small knots. On 

 March 26. 1912. one of these knots had grown rapidly in size, 

 the other had not changed." 



" Inoculations were made on small seedlings, July 20, 1910, on 

 the branches. Typical roundish knots or galls had developed 

 on September 5, 1910." 



[Silky] Oak {Grevillea robusta) (p.552), gave negative results, 

 " This is probably due to the slow growth of the tree." 



Under the heading of Other Galls that are at 'present little 

 under stood {p. bb'2}. — ^'Eucalyptus A''no^(pp. 55.3-554)— Galls occur 

 frequently on the small seedlings. These are hard knots that 

 occur always at the nodes. There will often be a gall on each 

 side of the plant where cot3ledons or the opposite leaves have 

 previously been. We have had small seedlings with these natural 

 galls under observation for about three years. In some cases 

 there is an increase in size in the knots, which still continue to 



