1908] HOLM—ALPINE GRAMINEAE 443 
known from the alpine regions of this country; others that are known 
also from the higher mountains of Eurasia;. some that have reached 
the polar regions, among which several are circumpolar; and finally 
some that occur also at lower altitudes in these same mountains. 
The alpine genera seem to be more cosmopolitan than those observed 
at lower levels; as a matter of fact none of these genera of Gramineae 
are endemic to this country, and none of the alpine genera of Europe 
and Asia are endemic to those countries. 
The habit and floral structures of the alpine Gramineae of Colo- 
tado are remarkably uniform and simple, when compared with some 
of the other species and genera from the lowlands. Corresponding 
with this uniformity in habit, we meet with no extraordinary devel- 
opment of any of the tissues. The anatomical structure is rather 
simple, and neither the stereome, nor the chlorenchyma, nor the 
stomata exhibit any feature that might be looked upon as character- 
istic of an alpine type. In this respect the alpine Gramineae differ 
from most of the other families, not so much, however, from the 
Cyperaceae as from the Juncaceae (Luzula and Juncus), and especially 
from the dicotyledons. The habit and internal structure of the 
alpine dicotyledons of Colorado are very distinct from those of their 
representatives which thrive at lower elevations in mountains or on 
the plains and prairies; very prominent distinctions of this kind I have 
observed in a number of alpine genera, as Ranunculus, Trifolium, 
Claytonia, Stellaria, Synthyris, Mertensia, Primula, etc. Whatever 
conclusions may be drawn from the various treatments of alpine 
plants in general, and especially in regard to “adaptations,” it must 
e borne in mind that the monocotyledons have so far been almost 
entirely ignored, although they are certainly of no small interest on 
account of their frequent occurrence and very wide distribution in the 
high alpine regions. It seems thus very unsafe to describe the alpine 
leaf “in general” without including the Gramineae, and for this 
purpose the present paper may be of some interest to future students 
of ‘alpine structures.” 
BROOKLAND, D. C. 
EXPLANATION OF PLATE XXX. 
Fic. 1.—Cross-section of root stele of Poa Lettermanni: End, endodermis; 
P, pericambium; PL, proto-leptome; PH, proto-hadrome. X 560. 
