472 RYDBERG: PHYTOGEOGRAPHICAL NOTES 
Scirpus pauciflorus Swertia palustris 
Scirpus caespitosus *Pyrola uliginosa 
Bistorta bistortoides Veronica Wormskjoldt 
Bistorta vivipara *Elephantella groenlandica 
Ranunculus affinis Amarella scopulina 
Thakictrum alpinum Amarella strictiflora 
Vaccinium oreophilum Antennaria nardina 
Primula Parryi 
To this formation belong also the following species restricted 
to a part of the region: 
Southern Northern 
Caltha rotundifolia Caltha leptosepala 
Ranunculus stenolobus Caltha Cheledonu 
*Senecio atratus 
Ligusticum Porteri 
WILLOW BOGS 
These willow bogs are not exclusively alpine, as most of the 
species there are found also in the subalpine region. They are not 
so common in the southern Rockies as they are in the northern. 
In Colorado, the shrubby species consist mostly of Salix glaucops 
and Betula glandulosa, although other species of willows, as for 
instance S. chlorophylla, are not rare. Kalmia microphylla is very 
local there. In the northern Rockies the number of species is 
increased. More species of Salix are found and S. chlorophylla 
becomes more predominant. Alnus sinuata is added to Betula 
glandulosa. Sometimes, especially in pockets on the northern 
slopes, the predominant plants are ericaceous, Viz., Kalmia 
microphylla, Ledum glandulosum, Phyllodoce empetriformis, and 
P. glanduliflora. In the Canadian Rockies evidently are added 
to these, Arctuos and Oxycoccus. The herbaceous plants are 
mostly the same as in the sedge bogs, Elephantella and Pyrola 
uliginosa being conspicuous, especially in the subalpine regions. 
The shrubby plants characteristic of the willow bogs are the 
following: 
- Salix chlorophylla Salix saximontana 
Salix glaucops Salix monticola 
