LIFE HISTORY OF A FERN 



151 



and leaf-stalk. There is always a terminal bud at the 

 tip of the fern-stem (and of the branches when any oc- 

 cur) ; and the leaves are usually attached just back of this 

 tip. The stems are commonly (though not always) 

 covered by hairs or scales (Fig. 106), and on their older 

 portions, at some distance back from the tip, may be seen 



Fig. no. — A, Upper epidermis; B, lower epidermis, of the fern, Drynaria 

 mcyeniana. (Camera ludda drawing.) 



the scars, or the ends of leaf-stalks, left by old leaves that 

 have died and fallen away. The rhizome bears true roots 

 (Fig. 107), and its tissues are differentiated into epider- 

 mal, fundamental, mechanical, and conducting systems 

 (Fig. 108). In tropical countries there are "tree ferns," 

 with upright stems, and this tj^e of fern is common 

 among the fossil plants of earlier geological ages (Fig. 109) . 



