ANNUAL REPORT. 194U 29 



tion vegetatively was attempted. There was little or no success wita 

 cuttings, treated or not, which were taken in spring and summer; bia c.t- 

 tings taken in late winter from the lower, not the upper, branches of a 

 tree about thirty years old rooted 70 percent in sand-peat in three .ponths 

 after treatment for 5 hours with indolebutyric acid 200 mg. per liter. 

 Similar cuttings failed to root without treatment, and treatment with 

 more dilute solutions of indolebutyric acid for 20 hours was too long. 

 Some of the results of this work were published recently." 



Solutions of root-inducing substances are more effective with cuttings 

 of some species if used at higher than room temperatures. December cut- 

 tings of Taxus media, in sand, rooted 70 percent without treatment, 80 per- 

 cent after treatment with indolebutyric acid (50 mg./l., 19 hr.) at an 

 approximately constant temperature of 65° F., 100 percent (and more 

 rapidly and with better roots) after similar treatment at an initial temper- 

 ature of 86° F. for 3 hours followed by treatment with the same solution 

 at 65° F. for 16 hours. November cuttings of Picca piingciis var. globosa 

 had their rooting improved by indolebutyric acid (25 mg./l.) applied at 

 an initial temperature of 86° F., falling to 65° F.; h\M there was no im- 

 provement when it was applied at a constant temperature of 65° F. 



Rooting of cuttings of several species, taken in late fall or early winter, 

 was more improved by treatment for 16 to 24 hours with indolebutyric 

 acid (50 or 100 mg./l.) in a sugar solution (2.5 percent) than by similar 

 treatment with indolebutyric acid in water. Cuttings of Pfitzer juniper 

 rooted 44 percent after treatment with indolebutyric acid in water, 100 

 percent after treatment with that acid in a sugar solution. Cuttings of a 

 species of Cytisus rooted 40 percent In 16 weeks after treatment with 

 indolebutyric acid in water, 60 percent in 7 weeks after treatment with 

 that acid in a sugar solution. Cuttings of Chauiaccyparis obtusa varieties 

 compacta and maginfica responded similarly. Cuttings of Taxus media and 

 T. media var. Hicksii rooted equally well, 100 percent, with either treat- 

 ment, but the best roots were on cuttings treated with indolebutyric acid 

 in a sugar solution. Cuttings of a variety of arbor-vitae and two varieties 

 of Norway spruce did not respond to sugar, but cuttings of Picca glaiica 

 var. conica rooted 40 percent without treatment, 55 percent after treatment 

 with indolebutyric acid in water, and 78 percent after treatment with in- 

 dolebutyric acid in a sugar solution. Cuttings of Sawara cypress rooted in 

 larger percentages after treatment with honey in solution, but there was 

 no response on the part of cuttings of tliree other species. 



Rooting of summer cuttings of Hinoki cypress and Pfitzer juniper was 

 more improved by indolebutyric than by indoleacetic acid. Rooting of 

 early July cuttings of a lilac was more improved by naphthaleneacetic acid 

 (100 mg./l., 5 hr., gave best results) than by indolebutyric acid. 



July cuttings of Stczcartia korcaiia rooted less well if made of tips of 

 shoots than if made to include all of the current year's growth. Best 

 rooting, 100 percent, and much better than the untreated, was of cuttings 

 treated with indolebutyric acid 50 mg./l., 20 hr. 



Optimum concentrations of indolebutyric acid and lengths of time of 

 treatment for cuttings of some other species were 25 mg./l., 20 hr., for 

 Cornelian cherry (in July) ; 100 mg./l., 20 hr.. for Rhododendron minus (in 

 November ); 50 mg./l., 20 hr., for Picca glauca var. conica (in November). 



' Doran, William L., Holdsworth, Robert P.. and Rhodes. Arnold D. Propagation of 

 white I'ine by cuttings. Jour. Forestry 3S:S17. 1940. (Contribution No. 372.) 



