LAKE TO FOREST OR PRAIRIE 



247 



grass (Fig. 357), Poa triflora, etc. Sampson thinks the first five 

 are the typical and most characteristic ones in the succession 

 that leads to the occupation of the prairie by the Andropogon 

 furcatus (Fig. 358), 

 which marks the climax. 

 In summer these swamp 

 grasses may be luxuri- 

 ant enough to pay for 

 cutting to secure the 

 coarse marsh hay (Fig. 

 359). 



Among the grasses 

 and sedges occur many 

 other plants, not in 

 masses so as to give 

 character to a whole 

 zone as do the grasses 

 and sedges, but still 

 frequently. The fern, 

 Aspidium cristatum, is a 

 common one in such 

 marshlands. Equisetum 



FIG. 361. Chick weed, Cerastium vulgatum 



362 



FIGS. 362-364: Fig. 362. Three species of Cardamine: C. Douglassii at left; 

 leaf of C. bulbosa, above at right; C. Pennsylvania, right below; Fig. 363. Mer- 

 maid weed, Proserpinaca palustris; Fig. 364. Skull cap, Scutellaria galerictdala. 



