STUDIES IN LAKE AND STREAMSIDE VEGETATION 



167 



It is often remarked that the flora of the western United States is much 

 like that in the eastern United States. However, only 27 per cent, of 



TABLE VI 

 Geographical Range of Families. Genera and Species 



Number represented at Redrock Lake 



Common to North America, Europe and Asia 



North America and Asia, not Europe 



North America and Europe, not Asia 



North America only 



Both East and West North America, not Europe or 



Asia. . . . : 



West North America exclusively 



Species 



140 



39 



4 



o 



97 



13 

 84 



* Castilleja, Milella, Pcnlslemon, Zygadenus. 



t Dodecatheon, Chrysopsis, Frasera, Lewisia, Telraneuris. 



t Lewisia. 



the species at Redrock Lake occur also in the eastern United States. 

 Thus it is seen that the flora of Redrock Lake is decidedly western. 



VII. Summary 



For purposes of reference it may be well to summarize briefly the 

 scope of the foregoing paper. It is an ecological study of a morainal 

 lake (Redrock Lake) in the Rocky Mountains of northern Colorado. 

 The lake has an altitude of 10,100 feet (3,080 meters). The vegetation 

 is of the sub-alpine type. The present work is the first attempt to make 

 an intensive ecological study of a Rocky Mountain lake. The contents 

 of the paper can be ascertained from the section headings which are 

 as follows: I, Topography and Geology; II, Climatology; III, Soil 

 Temperature and Moisture; IV, Zonation; V, Seasonal Aspects; VI, 

 Floristics and Distribution. 



A consideration of the past geological history, of the present topog- 

 raphy and geology, as well as of the various climatological and habitat 

 factors, are discussed in their relation to the present condition and com- 

 position of the flora of the lake. The arrangement of the zones about 

 the lake, their composition and relationships are indicated. The 

 following zones are recognized: (1) Lake zone, characterized by Nym- 

 phaea polysepala; (2) Sedge zone, consisting for the most part of five 



