10 T O R R E Y A 



months after the girdling of these stems 84 were found to be heavily callused 

 and cuttings were made of them, half having the callus dusted over with talc 

 containing 4000 p.p.m. of indolebutyric acid and the other half left untreated. 

 The cuttings were placed in the usual coarse sand medium in the propagating 

 box with bottom heat. In seven days roots had begun to form and in twenty 

 days 38 of the treated cuttings had rooted whereas only 23 of the untreated 

 cuttings had roots. This rooting had taken place more quickly than with either 

 marcottes or other cuttings previously tried and the roots were exceedingly 

 sturdv. in most cases the equal of roots produced by marcotted stems. 



These results led to a more extensive test of rooting what are referred to 

 hereafter as '"old girdled" cuttings. In the middle of December 1942, sufficient 

 stems were girdled and left on the plants to provide 100 cuttings. These cut- 

 tings were harvested on July 13. 1943. having developed typical large calluses 

 at the base. Fifty of these cuttings were placed in the propagating box without 

 treatment and 50 were treated with Rootone dust over the callus. At the 

 same time 100 cuttings of the same size were cut from the plant without pre- 

 vious girdling, half being treated with Rootone dust, the remainder being 

 left untreated, and all placed in the propagating box with the ''old girdled" 

 cuttings. Inasmuch as this test was conducted in the summer, use of bottom 

 heat to maintain a higher temperature differential at the base of the cuttings 

 than at their top was impracticable. 



All cuttings were examined for roots in ten days, on July 23, and again 

 seven days later on July 30, with the final inspection five days later on August 

 4, when the experiment was discontinued. 



The results of these experiments are presented in the two accompanying 

 diagrams, the first of which shows the number of cuttings that rooted in each 

 treatment and the rapidity with which they rooted. Xot only did untreated 

 "old girdled"' cuttings root in greater abundance than did untreated check 

 cuttings but their speed of rooting was even more rapid than with check cut- 

 tings treated with Rootone. Total rooting of untreated "old girdled" cuttings 

 was essentially the same as with Rootone treated check cuttings. The most 

 striking effect from the use of Rootone was to increase greatly the rooting of 

 the ungirdled check cuttings. It also increased somewhat the rooting of "old 

 girdled''' cuttings. The relative speed of rooting in any of the cuttings appears 

 not to have been materially affected by Rootone treatment. 



Diagram 2 shows the effects of the different treatments upon the type of 

 roots produced by the cuttings in diagram 1. It will be seen that only poor to 

 fair roots were produced by untreated, ungirdled cuttings whereas the use of 

 Rootone on ungirdled cuttings caused more than a third of them to produce 

 strong roots and a similar number to produce good ones. A much higher pro- 

 portion of untreated "old girdled" cuttings produced strong roots than where 

 Rootone was used on ungirdled cuttings but the use of this substance on "old 



