218 MISS SARAH M. BAKER ON THE 
over the marsh by the tide, or from young plants torn off the stones and 
caught in the vegetation of the marsh, is;hard to determine. 
Artificial Cultivations oj. Pelvetia.—In the summer of 1910 a few experi- 
ments were attempted in order to find out what effect certain physical and 
Fic. 9. 
= 
4 
(AQ 
974 
e 
Habit of Pelvetia canaliculata, var. libera. а and В show bunches of 
adventitious shoots. x1j. 
chemical factors had on the growth of P. canaliculata. A series of cultures was 
made with young plants, both from stones and from the marsh. е plants 
were placed in glass vessels and covered with sea-water at suitable intervals, 
