66 AMERICAN FERN JOURNAL 
of wide plains, having an altitude of from 3000 to 7000 
feet, broken here and there by low hills. In southern 
New Mexico, at the lower altitudes, these plains support 
only a sparse vegetation, although even this furnishes 
forage to thousands of cattle; but in the northern part 
the plains are covered with grasses and other herbaceous 
vegetation characteristic of the Great Plains and the 
Great Basin. 
If New Mexico were wholly arid one would expect its 
fern flora to be Jimited. The botanist acquainted only 
with the vegetation of the eastern and northern parts of 
the United States or that of the Pacific Slope, if he were 
seeking for ferns, would have hopes of finding at least 
a few in the higher mountains of the State. Strangely 
enough, most of our ferns are not found in the high 
mountains, but rather in the low arid ranges and foot- 
hills of the southern part of the State. The species 
which occur at higher altitudes are mostly those which 
have a wide distribution in North America, several of 
them extending to Eurasia. The fern flora of the arid 
mountains consists largely of species indigenous to the 
Southwest 
Ferns seem out of place in a xerophytic habitat, yet 
many of them grow nowhere else. A few miles southeast 
of Las Cruces is a low rounded mass of limestone known 
as Tortugas Mountain. Here, upon nearly bare, arid 
slopes, often among cacti, agaves, and other desert 
plants, grow five species of ferns. Several ferns are 
often associated with cacti in other places. Most of 
them are well fitted for existence in such situations by 
the thick texture of their fronds, which are often thickly 
covered with scales. In most cases the fronds, in arid 
locations, are involute or much shriveled under ordinary 
weather conditions, but when the summer rains fall 
they quickly unroll and growth again begins, although 
the period of moisture usually lnats for Hoe a few days 
ata time. 
oe ares op Bes 
tae: 
Soils FSS Ue Sees + 
