WATER REQUIREMENT AND ADAPTATION IN EQUISETUM 33 



systems, but the results with Helianthus show beyond a doubt 

 that it is able to draw water from the soil after Equisetum fluvia- 

 tile and Equisetum arvense are dead. Figure 2 shows Equisetum 

 fluviatile wilting while both Helianthus and Phaseolus are in 

 good condition. The conclusion to be drawn from this evidence 

 is that the latter are less hydrophytic than either Equisetum 



Fig. 2. Equisetum fluviatile wilting. Phaseolus vulgaris and Helianthus annuus 

 still turgid. 



arvense or Equisetum fluviatile. Equisetum hyemale differs from 

 the other two in that it seems to be mesophytic in its relations. 

 These results on the wilting of Equisetum, Helianthus, and 

 Phaseolus agree with the work of Hedgecock (1902:65) who 

 states, in his conclusion that "the ability of plants to take water 

 from the soil varies in an ascending scale from hydrophytes, 



