94 RyDBERG: PHyt APHICAL NOTES 
mountains farther south, as the Pyrenees, the Caucasus, the 
Himalayas, and, in America, in the San Francisco Mountains, 
Arizona. Like most bulbiferous plants, it does not readily propa- 
gate by seeds, but when these are formed, they may easily be 
distributed by the wind on account of their flatness. 
Juncoides spicatum has about the same distribution except that 
it is not found in the Himalayan region. The seeds of this species 
must have been carried by birds as they are too heavy to be carried 
by wind. 
Poa alpina extends south to the Sierra Nevada (Spain), the 
Appennines, and the Himalayas, and Trisetum subspicatum and 
Phleum alpinum extend in America south through the mountains 
of Mexico, Central and South America. As these grasses also are 
subalpine, their seeds have probably been distributed by animals. 
The following two species are common to the arctic regions of 
both hemispheres, to the Rockies, and to the Asiatic mountains, 
but not found in the Alps: Draba glacialis and Anemone parviflora. — 
Saxifraga cernua and Campanula uniflora are circumpolar 
glacial plants, but do not reach the Alps. They are found in 
America as far south as Colorado and Utah. Either these plants 
are of American origin and have extended their range over northern 
Europe, or else they have perished in the Alps. 
The same may be said about Micranthes hieracifolia, although 
it does not reach the southern Rockies. 
Aster alpinus is a glacial plant found both in the Alps and the 
Altai, rare in the Rockies and lacking altogether in the Scandinavian 
mountains. 
Some of the circumpolar glacial plants, although they are found 
on this continent, are found neither in the southern Rockies nor 
in Sierra Nevada, although they are found in both the Alps and 
the Altai. Such are: 
Cerastium alpinum Chondrosea Aizoon 
Erigeron alpinum Micranthes nivalis 
The first two are, however, represented by related endemic 
species. 
A few of these circumpolar plants are found in the Alps, but 
neither in the Altai nor in the southern Rockies, as for instance 
