326 Kansas Academy of Science. 



Late in May and early in June, 1908, I tested the following 

 twigs, all of which had made considerable growth : 



Class A. — Ulmus americana (2). 



Class B. — Populus deltoides (2), Ulmus americana, Gleditsia 

 triacanthos (2), Ailanthus glandulosus, Acer saccharinum, Acer 

 neguado, Asimina triloba (2). Ten twigs of seven species. 



Class C. — Juglans nigra (2), Toxylon pomiferum, Gleditsia tri- 

 acanthos, Cercis canadensis (2), Acer saccharinum. Seven twigs 

 of five species. 



None of the nineteen twigs examined gave entirely negative re- 

 sults, although in several cases bubbles were formed slowly and 

 from only a comparatively small proportion of the lenticels. On 

 the whole, however, lenticels seem to be open in greater numbers 

 in the spring than in the fall. But the fact that so many of them 

 are open in the fall and winter seems to be a point worthy of 

 further investigation. 



