466 Rydberg: Phytogeographical notes 



Northern Rockies 



Claytonia megarrhiza Hidsea carnosa 



Telesonix heucheriforme Senecio Fremontii 



Oxyria digyna Alsine americana 



Selaginella densa Ribes parvulum 



Pseudopteryxia Hendersonii Polemoniiim viscosum 



3. Alpine cliffs 



While the following plants are found elsewhere, they are char- 

 acteristic of the crevices of exposed cliffs : 



*Chondrosea Aizoon Oxyria digyna 



*Leptasea austromontana Aquilegia saximontana 



Antiphylla oppositifolia Polemoniiim pulcherrimum 



Anticlea color adensis Polemoniiim delicatum 

 Senecio petrocallis 



4. Alpine mountain seeps 



This formation usually is found between the mountain crests 

 and the meadows, but is more moist than either. Often the 

 mountain crest or mountain slope formation gradually changes 

 into the meadow. This is usually the case where no melting snow- 

 drift supplies the slope with more moisture throughout the sum- 

 mer; but where water is dripping or seeping down from the snow, 

 along brooks, and above subterranean water courses, there is 

 developed a formation, which as far as moisture is concerned 

 could be classified with the wet meadow, but the ground is more 

 rocky, the soil consists more exclusively of humus and most of the 

 plants are different from those of the true meadow. The grasses 

 and sedges are fewer both in number and in species, but otherwise 

 the same as those of the meadow, although the three Poas men- 

 tioned below are characteristic of these seeps, rather than of the 

 meadows. Characteristic plants of these seeps are the alpine 

 willows, alpine clovers, Sibbaldia procumbens, Rhodiola, species of 

 Ranunculus, Senecio, Polemoniiim and Juncus, Taraxacum scopu- 

 lorum, Mertensia alpina and its relatives, Myosotis alpestris, and, 

 above all, many species of Saxifraga and its allies. 



In the northern Rockies there is found a plant association that 

 may be counted here. On northern cold mountain slopes of 



