CHAPTER LIV. 



THE VEGETATION OF THE STRAND. 



I. Types of Strand. 



1077. Strand formations are usually so strikingly different 

 from other edaphic as well as from climatic formations that they 

 may be considered in a separate section. By the strand, or 

 beech, flora is meant the plant life growing along shores of 

 the water, usually lakes or seas. There are two general types 

 of strand, conditioned by the water-holding capacity of the soil. 

 These are the xerophytic, or dry strand, and the hydrophytic, 

 or moist strand. During surf action or rains the dry strand 

 is wet, but in the sandy soil the water leaches out quickly and 

 also evaporates rapidly from the surface, while on rocks the 

 water runs quickly off. Radiation of heat takes place more 

 rapidly also from a sandy soil than from a nitrophytic soil, i.e., 

 one with an abundance of humus. In the xerophytic strand the 

 gradient of the slope is steeper, so that there is only a narrow 

 zone of shallow water, or none, while in the hydrophytic strand 

 the gradient is low, giving a usually broad zone of shallow water 

 where the surf breaks before reaching the shore line. Here 

 there is usually an abundance of aquatic^ vegetation, and some 

 plants in this zone often act as surf barriers (certain species of 

 Cyperus, the flags, etc.). Between these two types of strand, 

 however, there are all gradations and modifications, so that for 

 purposes of study a farther subdivision is desirable, and often 

 different strands will have different composite elements, so that a 



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