34 
IOWA ACADEMY OF SCIENCES. 
and ferns, fungi and slime moulds: so that one is quickly im- 
pressed with the thought that the flora of the desert is but 
a transformation, a replica, in miniature sometimes, of 
that with which we are all familiar in happier or, as we 
think, perchance, more normal fields. 
It was, therefore, not without surprise that we found slime 
moulds in the desert. The filmy plasmic sheets and streams 
that creep in apparently aimless channels about our north- 
ern world would seem impossible in the hard conditions 
of the desert air where rains sometimes fail for months or 
even years together and even the dew is not infrequently 
forgotten. 
The New Mexican and Arizona deserts are, however, very 
varied in just this particular. These deserts are generally 
all high, three or four thousand feet above the sea, and are 
by no means level; they offer plains and hills, they are 
broken by mesas and ridges and mountains, mountains 
where we have an altitude of ten or twelve thousand feet. 
These high points, for reasons that the meteorologist must 
explain, gather the scanty clouds. Here also stands a lim- 
ited coniferous forest whose perennial foliage gathers the 
showers of summer and in winter sifts the snows and so 
holds on the tops of the mountains in wide scattered iso- 
lated groves, tufts of forest rising like islands over the far- 
spreading gray waste of the common Sahara. 
Now it is on these mountain-tops that all the species 
here listed are collected. Here fallen trees afford the 
necessary amount of decaying organic matter for abund* 
ant food, and once wet either by the melting snows of 
spring or the showers of summer, hold for months together 
in their rotten bulk the moisture that makes possible 
plasmodic life. In other words, although in the midst of 
the desert, a desert extending for hundreds of miles 
in every direction, we have, nevertheless, here true forest 
conditions and all the children of the forest here find 
place; here are oases and these afford conditions suited to 
the phase of vegetal life with which we are all familiar. 
