92 Otis F. Cuetis 



last of January, when this lot was taken up, the twigs treated with potas- 

 sium permanganate showed accelerated top growth. No actual measure- 

 ments were taken of this lot, but the root growth was fully twice that 

 of the checks. The buds of the lot placed in sand in the shaded house 

 opened soon after these. There was no apparent difference in time of 

 starting between the treated and the untreated twigs, but at the end of 

 about ten days those treated with potassium permanganate clearly showed 

 increased top growth. Similar results were obtained with the cuttings 

 placed in water in the cool room. 



Results obtained from experiments conducted in the spring of 1917 

 were very similar to those just described. On cuttings treated either 

 continuously or for a limited time with potassium permanganate, an 

 increased growth of roots ranging from 2.17 to 11 93 times that in the 

 checks was produced. Results following the placing of the cuttings in 

 sand after treatment for twenty-four hours in 0.1 molecular potassium 

 permanganate are shown in figure 4 (page 87). 



The buds on all the twigs in these experiments opened very soon after 

 the twigs were set out, and even before the roots started. For this reason 

 the stimulation cannot be explained as due to an effect which may bring 

 the basal, part of the twig out of the resting condition and leave the tops 

 dormant. These twigs apparently had completely passed the rest period, 

 and therefore any stimulation obtained cannot have been due to an effect 

 on the rest period. Furthermore, it has been shown by Howard (1915 b), 

 and by other investigators, that, so far as the rest period is concerned, 

 treatments which will exert a stimulating effect if applied during the rest 

 period will have no effect, or may even produce a retarding effect, if 

 appUed at or near the end of that period. ' 



True rest shown only by buds of woody cuttings. — The effect of stimulation 

 of root growth is evidently independent of the rest period, as already 

 stated. So likewise are callus formation and root development, which 

 proceed in untreated twigs whose buds are dormant. The buds of cuttmgs 

 taken on October 15 (fig. 5) did not start general growth until about 

 March 1, approximately four months after the cuttings were taken, while 

 the buds of twigs taken on December 8 started almost immediately. Those 

 taken on December 8 were well started by December 22, only two weeks 

 after the cuttings were made and more than two months earlier than 

 those taken on October 15. The roots in the untreated twigs, however. 



