BOTANICAL NOTES. 657 
On all the snowy mountains the genera are essentially the 
same. The species, however, are somewhat diversified. One 
mountain, for instance, produces a peculiar species of Gen- 
tiana; another a Draba ; while a third plant is common to 
two distinct snowy summits. But what appears still more 
remarkable is, that certain Ferns, whose light powdery seeds 
are so easily transported by the winds, should be restricted 
to certain localities. 
The Jamesonia is found in the greatest abundance on the 
grassy region of Cayambe, Condorasto, and the mountains of 
Cuenca ; but I believe it might be sought for in vain on 
Chimborazo, Cotopaxi, and Pichincha. Gleichenia simplex, 
Cryptogramma retrofracta (No. 59), Gymnogramma flabellata 
(No. 63), and Gymnogramma elongata, all very abundant on 
the mountains of Cuenca, do not at all occur on those of 
Riobamba and Quito, the ridge of Asuay forming the line of 
separation. 
On all the “ nevados,” the line of perpetual congelation 
may be placed nearly under the same parallel of altitude ; as 
the following table, founded on barometrical measurements, 
will sufficiently demonstrate; the results varying, however, 
with the season of the year, the limit being generally higher 
during the time of the vernal equinox. 
Cotopaxi (Dec.) , : : 15,646 feet. 
Chimborazo, (March) * : 16,000 
Antisana, (Oct.) ‘ r : 15,838 
Pichincha, summit of  . : 15,676 
(Very frequently without snow). 
Cayambe, (June) . : à 14,217 
Condorasto (Jan.) . E qe 15,600 
The western side of Pichincha, fronting the Pacific, is fre- 
quently obscured by dense fogs, sweeping across the face of 
the paramo, occasioned by ascending aerial currents, charged 
with moisture, intermingling with the cool mountain atmos- 
phere ; while that of the table land of Quito, unless when 
disturbed by the transient effect of a thunderstorm, 1s re- 
