go . Muhlenbergia, Volume 3 
in either the Hudsonian zone above, or the yellow pine belt be- 
low. 
HUDSONIAN ZONE 
Ascending Mount Rose at an elevation of between g100 
and 9200 feet, we have a contact of lava and granite. At this 
point the white bark pine (Pixus albicaulzs) is the only tree. It 
produces a trunk up to the 10000 foot contour, and from there 
on to 10600 feet it produces only prostrate branches. It was 
interesting to find these laden with cones. ‘The gravelly mead- 
ows of the open spaces among these pines are profusely covered 
with many different species of plants. The following list is 
given without attempting to define the exact localities of the 
different species: Senecio triangulartis, Cystopteris fragilis, Sol- 
wdago multiradtata, Ligusticum Grayt, Raillardella Nevaden- 
sts, Sibbaldia procumbens, Antennaria dioica, Ribes lentum, 
Erigeron ursinus? Rhodiola tntegrifolia, Stipa occidentalis, 
Polygonum Shastense, Pentstemon chionophilus, Eriogonum 
Lobbi, Pedicularis atiolens, Eriogonum marifolium, Mimulus 
primulordes, Lupinus leucophyllus. L. cytisowdes, L. Lyallit, Stipa 
occidentalis, Trifolium monanthum, Poa refiexa, P. Byckleyana, 
P. Sandbergu, P. Olneyi, Agrostis Rossae, Phieum alpinum. 
This was the upper limit of 77zfolium monanthum. It occurs 
in great quantities in the meadows at 8000 feet. The charac- 
teristic willow of this region is Salzx glaucops. 
ARCTIC ZONE 
The writer is inclined to regard the Arctic zone as begin- 
ning at the limit of trunk growth of the white bark pine, as the 
Arctic willow (Sax petrophila) occurs at this point. The 
character of the soil also changes from granite to andesite, bring- 
ing us again into the lava region. In addition to the prostrate 
form of Pinus albtcaulis, already spoken of, we find the follow- 
ing, given in the list according to their elevations from 10000 
to 10800 feet: Salix petrophila, Raillardella Nevadensis, As- 
tragalus Whitneyt pinosus, Dastophora frutiosa, Cerastium 
Behringianum, Arenaria acuteata, A. Nuttalliz, Oxyria digyna, 
