AQUATIC VEGETATION. 



629 



to light and suffer decoloration in the stronger-lighted strata. 

 In shady places the red algae grow nearer the surface; some 



Fig. S33b. 



Ascophyllum nodosum at low tide, Hunter's Island, New York City. (Photo- 

 graph by M. A. Howe.) 



species are bright red when they grow in the shade or dull red 

 when growing in brighter light. 



