198 BOTANICAL GAZETTE [MARCH 
The work of Ponp’ and the more recent work of THopay and 
SyYKEs® goes to show that submerged aquatics absorb, and pre- 
sumably exude, considerable quantities of water. Each of the 
two methods empioyed by Ponp showed absorption by the normal 
root system; the method of THopay and SyxEs showed an intake 
by cut shoots. The writer has not made any experiments with the 
ea 
0 
Fic. 6.—Form of apparatus used in determining the rate of leaf-absorption 
water. 
Hymenophyllaceae to ascertain if intact plants absorb with their 
uninjured root system when the leaves are wet or submerged. No 
evidence can be given, in other words, which is as satisfactory 4° 
that of Ponp for Ranunculus aquatilis. THopay and SYKES 
showed a rapid intake of eosin solution by the cut ends of shoots 
of Potamogeton, and, if the eosin method may be trusted, their 
experiments go to show that the transpiration stream is quite strons 
even when shoots are severed from the root system. As respects 
ND, ok MOND H., The biological relation of aquatic plants to the substratum. 
Sick U. S. Fish Comm., pp. 483-526. 1903. 
a and Syxes M. G., Preliminary observations on the transpiration 
current in submerged water plants. Ansils of Botany 23 :635-637- 1909- 
