Grossenbacher — Radial Growth in Trees. 15 



outer four rings. In the branch-bearing portion of the stem the 

 outer rings again showed some starch. All the wood was rich 

 in fats which usually exceeded the starch present. In the 

 phloem only the youngest cells had appreciable amounts of fat. 

 That is, in mid-July more fat and less starch is present in spruce 

 than in June. 



Very little starch occurred in the one-year roots but it in- 

 creased in amount toward the thicker roots so that in four-year 

 roots as much starch was present as there had been in the trees 

 cut before. The bark also contained much starch but very little 

 fat. No fat was present in the wood of the smallest roots but it 

 occurred in the larger ones and increased upward. The new 

 elongation growth of the roots and the bark on the thin ones, as 

 well as the young wood and phloem, were devoid of starch al- 

 though considerable was present in the large roots. Fat oc- 

 curred in the root wood and in occasional places in the bark. 

 , By the last of August an additional reduction had occurred in 

 the fat content of the bark and the starch in the bark had also 

 decreased from the ground upward while nearly the entire wood 

 cylinder had become practically starch-free. The bark of the 

 larger roots contained considerable starch but it was irregular- 

 ly distributed. In the youngest phloem it was absent. The 

 wood-rays in the larger roots and stumps had fairly large 

 amounts of fat present. In general it may be said that the 

 starch decreased in the aerial parts and increased underground 

 since last examined in July. The transition occurring at the 

 crown or stump where starch was less and fat more abundant 

 than earlier in the summer. 



On September 25 the bark of the stem contained considerable 

 starch but it was present in decreasing amount from the first 

 branches upward to practically none in the season's growth of 

 shoots. Nearly the entire wood cylinder was devoid of starch 

 excepting a small amount at its base or crown and in the inner 

 living rings. Both bark and wood were rich in fats especially 

 in the rays. The maximum fat content occurred about 3 m. 

 above ground where starch was practically absent. All except 

 the thin roots were comparatively rich in starch. In the wood 

 starch increased toward the stump. The larger roots also con- 

 tained considerable fat while the small ones had none. 



On October 28 the bark of the stem near the ground contained 



