348 RYDBERG: PHYTOGEOGRAPHICAL NOTES 
Herbs 
tEriophorum Scheuchert tArenaria norvegica 
alpinum {Drosera longifolia 
{tJuncoides arcticum | Condrosea Aizoon 
= arcuatum {Leptasea tricuspidata 
tOrchis rotundifolia 
II 
I. SPECIES NEARLY EQUALLY DISTRIBUTED IN THE ROcKIES AND 
THE PACIFIC MOUNTAINS 
There are many species which seem equally at home both in the 
Rocky Mountains, the Sierra Nevada and the Cascade Mountains: 
The larger part of these are more or less xerophytic plants growing 
in the drier part of the subarctic zone, especially on southern 
exposures. Nearly all of the plants listed below are also equally 
distributed in the Montane and the Subalpine Zones. To these 
belong four of the conifers, Pseudotsuga mucronata, Pinus Murray- 
ana, P. flexilis and P. albicaulis. Of these the last mentioned 
is the only one which is not better represented in the Montane 
Zone. Its distribution is also more extensive in the Pacific moun- 
tains, and it is not found in the Southern Rockies. It has therefore 
been placed among the immigrants, though its original home might 
bethe Northern Rockies. Pseudotsuga mucronata is also found in the 
mountains of northern Mexico. All extend north in the Rockies to 
about latitude 55 degrees, except Pinus Murrayana, which grows 
much further north in the Yukon Valley, at latitude 65 degrees. 
Trees 
Pseudotsuga mucronata Pinus flexilis 
Pinus Murrayana 
Shrubs 
Salix glaucops Ledum glandulosum 
Ribes montigenum Kalmia microphylla 
Pachystima myrsinites Gaultheria humifusa 
Phyllodoce empetriformis 
