—39— 



Aside from the cristation I cannot see that the plant differs 

 from ordinary spinulosa, and it is quite likely that this peculiarity 

 has been induced by the abnormal conditions of habitat. Ferns 

 deprived of their natural environment and grown under unusual 

 exposure to sunlight or in excessive moisture or drought often 

 take on odd forms; or to put it a little differently, inherent ten- 

 dencies toward variation gain remarkable impetus directly upon 

 modification of food supply, light supply and drainage. Often- 

 times when sports occur in a wild state there is no unusual con- 

 dition of environment apparent, nor need we assume that such a 

 feature is necessary; but there are many instances in which evi- 

 dently changed conditions appear as the immediate cause of 

 unique forms. The present case seems such an one. Of com- 

 mon examples of this, one of the best known occurs in the 

 Christmas fern (Polystichum acrostichoides) , of which variously 

 lobed and incised forms are known to be developed upon de- 

 forestation of the natural habitat. 



Adiantum modestum in Arizona. — Specimens in the U. S. 

 National Herbarium, collected by Mr. J. B. Leiberg (No. 5.968) 

 in Arizona, "along the Bright Angel Trail; alt. 1,100 meters; 

 September io : 1001," agree well with the material from Roswell, 

 New Mexico (F. S. and Esther F. Earle, No. 261) on which Dr. 

 Underwood recently founded his Adiantum modestum. Other 

 specimens from the same region seem to indicate that the line 

 separating this from much of the other southwestern material 

 still referred to A. Capillus-vencris is at best a doubtful boun- 

 dary. 



Polystichum munitum soutarium, subsp. nov. — Similar to 

 P. munitum; distinguished by the dark persistent chaff which 

 very thickly covers the rachis throughout, and by the narrower 

 and extremely coriaceous pinnae which are more scurfy below, 

 somewhat glaucous in appearance and possessed of abbreviated 

 decidedly cartilaginous appressed incurved teeth. 



Type in the Gray Herbarium ; collected by A. W. Anthony 

 on Guadelupe Island, Mexico (off the coast of Lower California) 

 July to October, 1896 (No. 9). An imperfect sheet of the same 

 collection and number is in the U. S. National Herbarium (No. 

 279439) . and Dr. Edward Palmer's No. 102. also from Guadelupe 

 Island, is the same plant (Gray Herbarium). 



