394 



ECOLOG Y. 



taking up quantities of water. Not all the cells of the leaf are 

 green, but alternate rows of cells become broadened, lose their 



chlorophyll, and their protoplasm 

 collapses on the inner faces of the 

 cell walls in such a way as to form 

 thickened lines, giving a peculiar 

 sculpturing effect to them. Perfora- 

 tions also take place in the walls. 

 These empty cells absorb large quan- 

 tities of water, and by capillarity it 

 is lifted on from one cell to another. 

 These pendent branches, then, which 

 envelop the sphagnum stem, lift 

 water up from tlie moist substratum 

 to supply the leaves and growing 

 parts of the plant which are at the 

 upper extremity. 



709. Year by year the extension 

 of the sphagnum increases slowly 

 upward by growth of the ends of 

 the individual plants, while the older 

 portions below die off, partly disin- 

 tegrate, and pass over into the in- 

 creasing solidity and bulk of the 

 peat. It thus happens sometimes 

 that the centers of such basins or 

 moors are more elevated than the 

 margins, because here a greater 

 amount of water exists in the depths 

 which is pumped up for use by the 

 plants themselves. Such a formation 

 is sometimes called a "high moor." 

 710. Because of the peculiar topographic features of these 

 basins, together with the conditions of moisture, etc., changes 

 in their form are quite readily observed. But no less important 

 are the influences of ])lants on soil conditions on the hills, and 



Two fruiting plants of sphagnum 

 (From Kerner and Oliver.) 



