32 



Esther Pearl Hensel 

 II. 



The effect of a temperature slightly higher than normal in 

 inducing a more rapid opening is shown by the following table: 



That Oxalis flowers should not yet be open at 8:35 a.m., April 

 29, 1905, and at 8:40 a.m.. May 3, with the same temperature or 

 practically so, 21.2"^ and 22°, and the light practically the same, 

 shows that the widely different relative humidities do not count 

 for much, 36 per cent in the first instance, and 82 per cent in the 

 other. Opening occurs at practically the same time, 9 130 a.m., 

 with temperature and light the same, but the relative humidities 

 still widely dift'erent, 31 per cent and 78 per cent. 



Several experiments, a half dozen at least, relative to the effect 

 of light in opening flowers, show, as for the other flowers ex- 

 perimented upon, that opening occurs as well when plants were 

 put into the shade tent as when in the open with full light. 



