Cambial activity in certain horticultural plants* 
LEWIS KNUDSON 
As stated by the writer in a previous publication,} there is a 
scarcity of data respecting the season of cambial activity in woody 
plants. This lack of knowledge, particularly with respect to cam- 
bial activity in the fruit trees, is the more surprising when one 
considers its significance to pruning and fertilizer practices, and 
since ultimately a rational system of fruit culture will be based on 
an accurate knowledge of the life history of the plant. It was in 
the hope of supplying some of the desired information that an 
investigation on this subject was begun in the summer of 1909.} 
It was found impossible to continue the investigation, except for a 
few observations made in the summer of 1913, but because of the 
scarcity of data on this subject it seems advisable to record the 
results of the observations made. 
OBSERVATIONS ON THE GRAPE 
' Methods.—For the investigation a number of vines were selected 
of the Worden variety (Vitis labrusca). They were uniform as 
regards size and conditions of growth. They had been growing for 
four years on a plot of land on the campus of Cornell University, 
Ithaca, New York. The vines were under the care of the Depart- 
ment of Pomology, and had been properly pruned during the 
previous seasons. 
At intervals throughout the season cuttings were taken from 
the one-year-old wood. These cuttings were removed in all 
cases from the basal internodes of different shoots and, as far as 
possible, from shoots of the same exposure and the same diameter. 
Cuttings from new shoots were likewise made from the basal 
* Contribution from the Laboratory of Plant Physiology, Cornell University. 
Tt Observations on the inception, season, and duration of cambium development 
in the American larch [Larix laricina (Du Roi) Koch]. Bull. Torrey Club 40: 271- 
293. pl. 18, 19. 1913. 
+ The field not Sree ¢ me de by Dr. George R. Hill, Jr. 
WIC ima 
