FLOWERLESS PLANTS. 



187 



FIG. 349. 



how these spots may be concealed under folds of the 

 margin of fronds. 



These brown patches certainly look very little 

 like flowers. Examine them never so carefully with 

 your microscope, you will not 

 find stamens or pistils. And 

 yet these little brown patches an- 

 swer, in a certain way, to seeds. 

 It is from them that new ferns 

 arise. They are the reproduc- 

 tive parts of this class of plants, 

 and the fronds that bear them 

 are said to be fertile. Examine 

 these spots carefully with your 

 magnifying -glass, and compare 

 them with Fig. 345 or Fig. 349. 

 The small, brownish clusters of 

 fruit-dots seen on the under sur- 

 face of fronds, in rows along the veins, or on the 

 margin of the pinnae, are called sori, and a single 



FIG. 350. 



FIG. 851. 



cluster a sorus. The scale or protective covering 

 of a sorus, seen in Fig. 349, but absent in Fig. 345, 



