SOUTHERN CALIFORNIA FERNS 99 
ferns (Notholaena tenera and Cheilanthes Feei) of wider 
distribution beyond the limits of the state, one of which 
is known within it by a single collection, the other by 
only four or five. The rain belt exhibits nothing of 
this; its ferns are of wide-spread species, and its most 
prominent one is of cosmopolitan distribution. 
The arid regions are the homes of Pellaea, of Notholaena 
and of Cheilanthes, all ferns modified by the conditions 
under which they exist. These modifications are two- 
fo'd, and affect the structure of the plant, and its manner 
of life, and I do not recall a southern California species 
of these genera which does not exhibit both of these 
characteristics in some degree. In structure, in addition 
to histological modification, there are the external 
adaptations manifested in the small size of the frond 
and the multiplication of its divisions into contracted 
pinnae which are often broken up into bead-like tessel- 
lations. The fronds are thick, the opposite extreme 
in fern structure from the filmy ferns, which grow at the 
opposite extreme of conditions, but with which they are 
connected by a long series of ferns of intermediate 
structure, the results of adaptations to al] the intermedi- 
ate conditions. All but one of these ferns have evolved 
organs which serve to protect them in some degree 
from too great transpiration, to which they are exposed 
by the excessive insolation, the arid air and the drying 
winds of their habitat. Cheilanthes viscida has a coating 
indicated by its specific name; Notholaena cretacea and 
Gymnogramme triangularis a powdering of yellow or white 
grains; Notholaena Parryi is densely woolly, and Notho- 
laena Newberryi has a close cottony tomentum; Cheilan- 
thes Fendleri is clad in scale armor, and Cheilanthes 
fibrillosa has fibers mingled with its scales. 
The other adaptation affects the habits of these ferns; 
their life-histories. Ferns, I take it, are normally ever- 
greens, enjoying an uninterrupted growth, each leaf 
