10 MASS. EXPERIMENT STATION BULLETIN 435 



nated below as sand-sphagnum peat or sand-sedge peat consisted of two parts 

 sand and one part peat by volume. 



It is commonly believed, and probably with good reason, that the rooting 

 medium for cuttings of most plants should be fresh, clean, and relatively free 

 from soil-infesting fungi. But cuttings of some species may root better in un- 

 sterilized sandy soil or in a rooting medium in which cuttings have been previously 

 rooted than in one freshly prepared (5). There was good rooting of white pine 

 cuttings in a sand-peat mixture that had been previously used (6) and results 

 with used sand-peat led one earlier investigator (23) to suspect that fungi may 

 be beneficial in the rooting medium for cuttings of white pine. 



Cuttings of white pine taken from three trees on February 2 and treated with 

 indolebutyric acid (200 mg./l., 5 hr.) rooted 7 to 27 percent in new and freshly 

 prepared sand-sphagnum peat, 7 to 32 percent in old sand-sphagnum peat which 

 had been similarly used the previous season. So there was here no evidence 

 that the older material was superior. Cuttings of Piniis pumila Reg. taken at the 

 same time and similarly treated rooted 43 or 44 percent in this rooting medium 

 whether or not it had been used before. 



Old sand-peat was used more often than the new, simply because it was more 

 convenient. 



Old sand-sphagnum peat unsterilized was compared with the same sterilized 

 by steaming sixteen days before the insertion of cuttings. Untreated cuttings 

 taken January 6 from three white pines rooted not more than 10 percent in either 

 medium. After treatment with indolebutyric acid (200 mg./l., 5 hr.), cuttings 

 from one tree rooted equally- poorly in both media, cuttings fro.m a second tree 

 rooted ii percent in both media, and cuttings from a third tree rooted 56 percent 

 in the sterilized medium, 58 percent in the unsterilized. Similarly treated cut- 

 tings taken March 2 from one tree rooted 14 percent in either medium, while 

 those from another tree rooted 65 percent in the unsterilized medium, 62 percent 

 in the sterilized. 



The indications are, then, that sterilizing the rooting medium, while not 

 injurious, is of no benefit, cuttings which fail to root well in the unsteamed medium 

 also failing to root well in the steamed. The fungus Rhizoctonia was found on 

 the bases of some dead cuttings in both. This is not surprising, for so many weeks 

 must elapse between the insertion of white pine cuttings and their rooting that 

 there is ample opportunity for the contamination or reinfestation of sterilized 

 rooting media. 



Some work was also done with a rooting medium consisting of two parts sand 

 and one part soil containing pine roots and mycorhiza from under white pine 

 trees. This was compared with a mixture of sand and the same soil freed of fungi 

 by earlier steaming and with freshly prepared sand-sphagnum peat. In no case 

 did cuttings root any better in the medium containing mycorhiza than in those 

 without them. Cuttings taken from three trees on Januar}' 6 and treated with 

 indolebutyric acid (200 mg./l., 6 hr.) rooted from 18 to 37 percent in sand-peat, 

 not more than 20 percent in sand-soil with mycorhiza or in sand-soil after steam- 

 ing. Cuttings taken from three other trees on February 2 and treated with indole- 

 butyric acid gave similar results, higher percentages rooting in sand-peat than 

 in the other media. 



There is here no evidence to support the view that the presence or absence of 

 mycorhizal or other soil fungi in the rooting medium is an important factor 

 affecting the rooting of cuttings of white pine. 



It should be added that mixtures of sand and garden loam, useful as they may 

 be with the cuttings of some kinds of plants, never gave as good results with 

 cuttings of white pine as did sand or a sand-peat mixture. Thus, for example, 

 cuttings taken March 31 and treated with naphthaleneacetic acid (100 mg./l., 



