102 AMERICAN FERN JOURNAL 
or an abundance of moisture, and some shelter from the 
sun’s too-powerful rays, there are a number of semi- 
arid and of moisture-loving species. 
By a semi-arid fern I mean one that has some of the 
physical or habital characteristics of the arid species, 
or has developed independent methods of meeting the 
same necessity, namely, of retaining life through the heat 
and drought of summer. Such a fern is Cheilanthes 
Californica. This has the small and exceedingly divided 
frond of an arid fern, but it is entirely without any pro- 
tective indument. It grows at the foot of cliffs, where 
it obtains shelter from sun and wind, and where it is 
reasonably sure of a supply of moisture for a considerable 
period. When that fails it remains dormant until the 
next winter. Adiantum emarginatum is without pro- 
tection to its fronds, which have broader and less divided 
pinnae, consequently it also seeks the protection of 
cliffs, or other shelter, and reliable water for its roots, 
and when at length moisture dries up the fronds wither 
and die, and only the root remains alive, I am inclined 
to put Polypodium Californicum also in this class, al- 
though its only claim to inclusion is the fact of its summer 
dormancy. Its rhizomes creep along the crevices of 
shady cliffs in canyons. It starts into growth very 
early in the winter, unless the season is unusually dry 
and late, and in the most favorable places it is able to 
put in a long working period, but sooner or later the 
rocks become dry, and its foliage withers and dies. 
Apparently it needs a summer rest, for it does not grow 
where there is permanent moisture, although such places 
are available. There is another form of this species, 
seldom seen, which grows on open grassy banks. There 
the effect of the exposure is seen in the thick texture of 
its much smaller fronds, but its habit is like that of 
the common thin-textured form of the rock crevices, 
winter growth and summer dormancy. 
