THE LIFE OF A FERN. 



13 



according to their greater or less number will the 

 fern require a moister or dryer atmosphere. Should 

 the air of the fern-house or case become too dry, 

 and the plant be insufBciently watered, the evapo- 

 ration of water from the stomata will exceed the 

 supply from the earth, and the fronds will soon 

 become wilted. If a fern of less active habit be 

 placed in too moist an atmosphere, and too pro- 

 fusely watered, it will not endure the wrong condi- 

 tion, but mould and die. Some ferns, however, 

 possess the power of enduring great extremes of 

 moisture and drought. Such is the case with 

 many of our South-western species, where, in the 

 dry season, the fronds curl up, and remain in that 

 condition till again revived in the wet months by 

 the rain. Their roots doubtless penetrate deeply 

 into the crevices of the rocks where the plants 

 grow ; and great vitality is retained in the crown 

 from which the fronds spring, and which, like the 

 fronds themselves, is often protected by a dense 

 coat of soft scales. The two species Cheilanthes 

 lanuginosa (PI. 10) and Notholcena dealbata (PI. 2) 

 are examples of this habit. 



The writer received from a friend a plant of 

 Cryptogramme crispa^ which had been collected in 

 California two months before. No pains had been 

 taken to preserve the roots ; there was no earth 

 with it ; nor had the plant received a drop of 

 water during the entire time which it had spent 



