390 B u r n s and H e d d e n, Conditions infLuencing regeneration of livpocotvl. 
what had been tlie underside but was now tlie side turned to- 
ward tlie window. (Fig. 4, b.) 
Another set (Fig. 4 a) of decapitated seedlings were placed 
in a dark eliamber with tlie light admitted from one side only. 
After seven days numerous bnds appeared but all were on tlie 
side turned toward the window, with no tendency toward either 
end of the hypocotyl. 
The crowding of buds on one side is well shown in fig. 1 
and fig.. 4. These experiments show that light, and a rather 
strong light is the direetion power in the distribution of bnds, 
at least in the case of Linum. Observations on the otlier plants 
make it probable that it has the same influence with other plants. 
Finally it was thought that perhaps the light was a factor only 
in so far as it produced food material and that this was the 
Fig. 4. Linum usitatissimum. 
a b. Seedlings showing the effect of light on the position of shoots. 
Direetion of light indicated by arrows. Antirrhinum c. Same as a and b. 
direetion force. According seedlings whose cotyledons were 
enclosed in Piaster of Paris cast, were placed in the dark. 
These seedlings in no case produced buds although there was 
still present food material in the cotyledons. 
Discussion. 
hen we compare the results obtained from the above ex¬ 
periments and observations with those recorded by writers we 
find many points of contact. 
1. Tlie wound is not the cause of the development of 
„adventitious“ stems. This is shown in at least three cases: 
a) development of buds on injured plants in damp chambers, 
in small pots etc., 
b) development of one or more buds at the base of the 
hypocotyl near the end of the growing season and 
c) the production of buds on the hypocotyl when the 
cotyledons are enclosed in Piaster of Parisor remain 
the seed coats. 
b Winkler, Ber. d. Deut. Bot. Gesell. XX. 1902. p. 31. 
