»31)0 Hu r 11 > aiul 1 1 i'dd (■ II . ( "onditions inliucriciiij;- reyvni'ral iuu ut livpipcolyl. 



wliat had beon tho undersido but was ikjav tlio .sido turned to- 

 ward the window. 'Fig. 4, b.) 



Aiiotlior sot (Fig. 4a) of docapitatod secdlings were placed 

 in a dark chaiiiber witli tlic light adinitted from one side oiily. 

 After seven days munerous buds appeared but all were on tlie 

 side turned toward the window, with no tendency towaid either 

 end of the hypocotyl. 



The crowding of buds on one side is well shown in fig. 1 

 and lig. 4. These experiments show that light, and a rather 

 strong light is the direction power in the distribution of buds, 

 at least in the case of Linu»/. Observations on the other plants 

 make it probable that it has the same influence with other plants. 

 Finally it w^as 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. 

 Direction of light indicated by arrows. Antirrhinum c. Same as a and b. 



direction force. According seedlings whose cotyledons were 

 enclosed in Plaster 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. 



Disciission. 



When we compare the results obtained from the above ex- 

 periments and observations with those recorded by writers we 

 find many points of contact. 



1. The 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 Plaster of Paris ^) or remain 

 the seed coats. 



1) Winkler, Ber. d. Deut. Bot. Gesell. XX. 1902. p. .31. 



