266 



Mac Dougal, 



lower internodes of the stem, which were almost as long as the main 

 root. The first leaf was of orbicular outline, sometimes cut nearly to 

 the base, while in other specimens the first, second and sometimes the 

 third leaves showed only crenation. The fourth leaf was visible on 

 many of the seedlings on the above date (Fig. 1). 



Aquatic seedlings developed an axis longer than that of the terres- 

 trials with a slender main root of greater length and with fewer branches. 

 The primary leaf was of a Avidth not more than one-third of that of the 

 terrestrial, not entire in any instance, but never divided to the base. 

 The second and third leaves departed less from the form of the nepionlc 

 leaf than did the same organs in terrestrial plantlets {Fig. 2). Deve- 

 lopment was terminated in everycase in five or six months after germination 



and no adult plants were secured from 

 aquatic germinations. This result in- 

 dicates that the seedling was exposed 

 to an extreme of conditions and the 

 divergence was probably as wide bs 

 might be produced. The death of 

 the young plants may be ascribed to 

 the unsuitability of the leaves for 



photosynthesis under submersion. 

 Terrestrial plants a year old were of 

 course able to endure submersion and 

 produced finely dissected leaves com- 

 parable in spread and length with others 

 unfolded in the air. So far as the 

 forms of the leaves are to be taken 

 into account the diversity noted above 

 was well within the range of variation noted by ShuU in seedlings grown 

 as terrestrials. 



Some experimental cultures were begun in 1902 which might 

 afford further opportunity for testing the generalizations noted above 

 and also yield some information bearing upon the transmission of 

 environic effects to successive generations. The present contribution is 

 concerned with the first named subject: the inheritance of environic 

 effects, or the transmission of ^acquired" characters is being treated in 

 an extensive series of cultures at the various plantations of the Depart- 

 ment of Botanical Research of the Carnegie institution of Washington, 



and it would not be profitable to discuss the fragmentary results now 

 available. 



Fig, 2. Seedlinga of Sium germinated 



as aquatics. 



