STUDIES IN LAKE AND STREAMSIDE VEGETATION 1 57 



needles on the ground to form a non-conducting surface covering. The 

 soil therefore becomes very warm and dry because of intense insolation 

 (see Tables III and IV) . Most characteristic of these situations are the 

 early- flowering mat plants such as Arenaria sajanensis and Eritrichium 

 argenteum which are true alpine species. 1 Plants which flower some- 

 what later are: Aragallus multiceps minor, Pulsatilla hirsutissima. 

 The Selaginellas come to fruit in early summer or late spring. Summer 

 bloomers are generally just the ordinary forest plants, such as would 

 occur where there was little shade: Senecio, Aragallus, Artemisia, 

 Chrysopsis, Frasera. There is no autumn flora, as the soil becomes too 

 dry for plant growth at that season. It is seen that the spring flora is of 

 alpine type while the summer flora has rather montane and foothill 

 affinities. 



Dasiphora Associations. — This name is given to the plants of moister 

 forest openings near the lake. Excellent examples are seen to the 

 northwest of Redrock Lake and also at the southeast. These areas are 

 either entirely within the forest or else bounded by the forest on three 

 sides. Soil moisture is found to be intermediate in amount between 

 what obtains in the shrub zone and the moist forest. The dominant 

 species is Dasiphora fruticosa which forms scattered clumps about a 

 meter apart leaving ample unshaded space for herbaceous plants. 

 These latter are a mixture of mesophytes and xerophytes. Spring- 

 blooming plants are not conspicuous. In summer there are such dry- 

 country species as Antennaria, Sedum stenopetalum, Solidago and 

 Lupinus side by side with moisture-requiring forms: Elephantella, 

 Pentstemon glaucus stenosepalus, Castilleja sulphurea, Polygonum vivi- 

 parum. This mongrel population indicates, of course, that the associ- 

 ation is not a stable one but in a transition stage. From studies made 

 elsewhere by the authors it is known that this stage may lead directly 

 to Engelmann spruce forest, or that there may be an intermediate stage 

 of aspen grove (Populus tremuloides). The autumn flora of the Dasi- 

 phora association is characterized by two or more species of gentians 

 often in considerable numbers. 



1 In early spring this association is of alpine type and may be correlated with the "dry meadow" — a very 

 inappropriate name — of Cooper in the article previously cited. 



