558 Floristik, Geographie, Systematik etc. 
writer presents in this paper a treatment of the Gramineae, of which 
he observed seventeen species of the following genera: Phleum, 
AgrostiSj Calamagrostis, Deschampsia, Trisetum, Avena, Poa, Festuca 
and Agvopyrum. The geographical ränge is given, and three tables 
show their distribution. Four of these are circumpolar: Trisetum 
subspicatum, Poa ßexuosa, P. alpina, and Festuca ovina var. supina. 
The other species are either endemic to Colorado, or they occur, 
also, on the Pacific and Atlantic coasts; several are dispersed 
throughout the mountainous districts farther south in Europe and 
Asia. The altitude where these alpine species were collected lies 
between 3350 and 4300 M. Some of these occur, also, at lower ele- 
vations in these same mountains for instance Phleum alpinum, 
Calamagrostis purpurascens , Deschampsia caespitosa , Poa rupicola and 
Festuca ovina. A comparison is drawn between this particular grass- 
vegetation and that of other mountains of Switzerland, Spain, 
Norway, the Caucasus, and the Himalayas. The tribes are the 
same except that some few members of the Phalarideae are reported 
from the Himalayas; in regard to the genera the alpine flora ap- 
pears to be more cosmopolitan than that of the lower levels. In 
respect to the general habit of these alpine species, they do not 
exhibit an} T characteristics which might indicate the extreme condi- 
tions under which they live; the habit and floral structures are 
indeed remarkably uniform and simple, when compared with some 
of the other species from the lowlands. 
The internal structure is described and flgured of the roots, 
the culms and the leaves. Of these the root-structure is very uniform. 
In Agvopyrum the cortex is stereomatic in the peripheral strata, 
otherwise the cortex is generally thinwalled, and solid, or sometimes 
radially, collapsed as in some of the Poae. The pericambium was 
found to be continuous in all the species, and consist of a single 
layer except in Agvopyrum and Avena where tw T o to three layers 
were observed. In regard to the eontinuity of the pericambium it 
may be mentioned, that Klinge observed in European material of 
Deschampsia and Festuca ovina that the proto-hadrome vessels had 
broken through this tissue thus bordering on endodermis, while in 
the Colorado specimens the pericambium proved to be continuous 
in all the roots examined. The writer, however, calls attention to 
the fact that he has observed a varied structure in this respect in 
the same root of several Cyperaceae and Friocaulaceae, hence it does 
not seem that the position of the proto-hadrome offers any character 
to be depended upon. 
A much more varied structure is possessed by the culms, espe- 
cially in regard to the diposition of the stereome; the eleventh type 
of Schwenden er, which is the most frequent in this family, is, 
also, characteristic of the alpine species, as illustrated in five dia- 
grams. Five distinct structures occur in these, depending upon the 
presence of one or two circular bands of mestome-bundles, which 
mostly occur in two sizes, and alternating with each other. The 
cortical parenchvma is generally very compact in these Gramineae, 
sometimes as a palisade-tissue of several strata, or as a homogeneous 
parenchvma of short, roundish cells. The pith is thinwalled, and 
hollow. In the leaves the Stomata occur mostly on both faces, but 
as a rule they are most frequent on the ventral; they are often 
sunk, and covered by papillae or hairs. A very firm structure is 
possessed by the chlorenchyma, which mostly consist of palisades; 
the stereome, on the other hand, is poorly developed. In comparing 
