﻿286 



BOTANICAL GA/.I'.TT I: 



the use of this method for sprouting tubers that light exercises an 

 influence on the growth processes in the buds. Immature tubers 

 with slightly suberized skins produce sprouts under the influence of 

 subdued light and moisture almost as quickly as they do with the 

 skins removed; see tables XIV and XVIII. 



The foregoing light effect is entirely balanced when the skins 

 are removed; for sprouting occurs just as early in the dark as in 

 subdued light, other conditions being comparable (table XIX). 



TABLE XIX 



Four lots of 5 tubers each were chosen from immature McCor- 

 mick potatoes harvested on September 20 and immediately planted 

 in pots with the stem ends in the soil. The projecting seed ends 

 of the 4 lots were covered as follows: (1) a double-walled bell glass 

 filled with a solution of ammoniacal copper sulphate; (2) a similar 

 bell glass filled with a nearly saturated solution of potassium dichro- 

 mate; (3) a clear bell glass; (4) a black-walled bell glass. By 

 means of bent tubes the air under the bells was in free communi- 

 cation with that on the outside. Through these tubes water was 

 added daily to each pot in sufficient amounts to maintain under the 



