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FLORA OF THE CASCADES 145 
nunmilus, Delphinium, Saxifraga, Viola, Epilobium, Pentstemon, 
Mimulus, Pedicularis, and Arnica, are especially in evidence. 
Pinus contorta is abundantly infested with a diminutive mis- 
tletoe, Razonmofskya americana. 
While encamped in this neighborhood, several days were spent 
investigating the plant and animal life of one of the Three Sis- 
ters, which are among the highest peaks in the Cascades of 
Oregon. The three mountains are in close proximity to each 
other, and retain sufficient snow to support several glaciers. 
The summit of the Middle Sister is about six miles from the 
nearest point on the road we were following. This is the only 
one of the three peaks visited. The flanks of the mountain in 
many places are fashioned into exceedingly rough and precipi- 
tous ridges and chasms by volcanic action, some of the lava 
flows being so recent as scarcely to support any vegetation. In 
other places, however, the slope is more gentle and even, and 
there is a good layer of soil. 
As one begins the ascent from the 1600-meter elevation where 
we were encamped, the character of the vegetation is seen to 
change rapidly. Pinus contorta and Abies nobilis begin to thin 
out, and Tsuga mertensiana soon becomes the dominant conifer. 
A great variety of Hudsonian plants appear, at first as scat- 
tered individuals, but becoming more and more numerous. At 
about 2000 meters there is a fine pure growth of Tsnga mertensi- 
ana, with the ground beneath almost entirely devoid of smaller 
plants. When this has been passed the trail crosses several of 
the rough steep lava ridges, where Pinus contorta and P. mon- 
ticola barely persist and just reach the lower limit of Pinus 
albicaulis. 
Having crossed the last of the lava ridges, one finds himself 
on the bank of a tumbling torrent of milky water that issues 
from a glacier some two miles farther up. the slope. The true 
Hudsonian zone is now reached. Here are growing in abun- 
dance Juncoides piperi, Salix commutata, Pulsatilla Occident alis, 
Ranunculus eschscholtzii, Mitella pentandra, Lutkea pectinata, 
Potentilla flabellifolia, Lupinus alpicola, Phyllodoce empetri- 
formis, Cassiope mertensiana, Valeriana sit.chensis, and Agoseris 
alpestris. This is within 400 to 500 meters of the forest line, 
and at the date of our visit, July 15, considerable areas were 
still covered with deep drifts of snow, that grew more extensive 
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