LIFE HISTORY OF A FERN 



have died and fallen away. The rhizome bears true roots 

 (Fig. 2), and its tissues are differentiated into epider- 

 mal, fundamental, mechanical, and conducting systems 

 (Fig. 3). In tropical countries there are "tree ferns," 



FIG. 6. Osmund a Claytomana. Young sporophylls, showing circinate 

 vernation. Note the spore-hearing pinna?. 



with upright stems, and this type of fern is common 

 among the fossil plants of earlier geological ages (Fig. 4). 

 There are also climbing ferns. 



3. Two Kinds of Fern-leaves. Careful examination 

 of the leaves of certain mature ferns will disclose the fact 



