EVERGREEN FERNS. 



It is interesting to note the behavior of different 

 ferns when cold weather comes upon us. Many are 

 killed outright, but others last until the following year. 

 After a frost it is useless to look for Phegdpteris hexa- 

 gonopiera or Dicksonia. Adiantum palatum survives 

 a few frosts but it is soon brown and dead. In many 

 ferns, only the fertile fronds, or at least the fertile parts 

 of the fronds, die in winter. Aspidium acrostichoides 

 is a familiar example. Ly god in m pal main m, Aspidium 

 cristatum, Woodsia obtusa, Botrychium tcrnatum and 

 others act in this way. The latter species turns to a 

 reddish-bronze color and is very much prettier than 

 when green. When the fertile part begins to die, it is 

 in almost all cases at the top of the frond where it be- 

 gins to turn brown. The only exception to this that I 

 know of is Lygodium palmdtum. 



Some ferns do not seem to know whether to die or 

 not. In Asplcnium cbcncum the fertile fronds fre- 

 quently remain green the entire winter. Usually all 

 the fronds of this species become very much bleached 

 and covered with whitish spots and blotches. We no- 

 tice the same thing with Woodsia obtusa at times. The 

 fertile fronds of the latter usually die, but the only 

 thing that seems to stop its growth is freezing weather. 

 This fern and Asplenium trichomanes seem to put forth 

 the young fronds a little more on every good warm day 

 during the winter. Sheltered in the clefts of rocks, 

 and receiving warmth from them, since in winter the 

 ground is always several degrees warmer than the air, 

 they take ever}- opportunity to grow. The fronds of 

 A. trichomanes usually remain green, but one thing is 

 quite noticeable in pressed specimens — those which are 

 collected in winter lose their pinnae very readily, the 



118 



