1908] HOLM—ALPINE GRAMINEAE 431 
caespitose or sometimes stoloniferous, but with simple culms, and 
with an inflorescence (spicate or paniculate) of the usual composition. 
The empty glumes show no peculiar structure, and the flowering glume 
is either awned or awnless, and not in any way different from the 
usual structure among grasses in general. The average height of 
these alpine Gramineae is in some cases much less, in other cases. 
about the same as that of lowland species of the same genera. Poa 
Lettermanii, the species of Agrostis, and Festuca ovina are mere 
dwarfs, but Agropyrum Scribneri reaches a height of 50°™, even at 
an elevation of 4ooo™. Agropyrum violaceum at the same altitude 
has culms about 40°™ high; and the culms of Deschampsia caespitosa, 
Calamagrostis purpurascens, and Poa gracillima reach about the same 
height. In habit the alpine Gramineae do not exhibit any character- 
istics which might indicate the extreme conditions under which they 
live. The same is the case with those grasses that occur in the arctic 
tegion, where we meet with several species that do not occur farther 
south, but the habit of these is of the same general kind. It is very 
different with the representatives of most of the dicotyledonous families 
from the alpine and arctic regions; in these the habit is frequently 
so peculiar and characteristic that they are readily recognized as 
being either alpine or arctic. In other words, the monocotyledons, 
at least the Glumiflorae, do not appear to be influenced to any great 
extent by climate and soil, as are most of the dicotyledons, at least not 
in regard to their general habit in alpine or arctic regions. 
An examination of the internal structure of these alpine species 
from Colorado will demonstrate probable characteristics in structure; 
“probable,” because I am not in a position to make any comparison 
with species from other alpine regions. It is my intention merely to 
present these anatomical data for future comparison, when some- 
one may feel induced to investigate the grass vegetation of other 
Mountains, and especially from high altitudes. I have examined 
Toots, culms, and leaves. The leaf structure might have been suffi- 
Cient, and, as already stated, most authors have so far confined their 
Work to the leaves alone. However, it does not appear to me that the 
structure of culms and roots should be neglected altogether, and 
especially not when dealing with plants that are able to persist under 
Such extreme conditions. : 
