62 IP s t e I s i a 



CJuiiincl bed — Amonjjj the boulders of the 

 river channel and in the hollows and crevices of 

 the large rocks a few hardy types have gained a 

 foothold . A few of these are perennials and as 

 such must Ijear the yearly winter inundation. 

 The forms most commonly noted in this habi- 

 tat are: 



Hcuchcra a^ldbni CJadothanuius pyrolijlorus 



Mold sp. Erigci'oii philadclphiciis 



Chamcenerioji hitijoHuui Lu'nia hypoleuca 

 A riiicd diitplcxicdiilis 



In no instance do these plants become closely 

 associated into groups or societies but occur 

 thinlv and scattered wliere enough soil is present 

 to sustain them. Clddolhduinus pyrolifloriis 

 grows as a small slirub less than a meter high, 

 upon the large rocks in the channel and also 

 upon the rocky banks of the river. Chdiiiac- 

 iicrioii IdlijoIiitiJi, Erigcroii philddcl phiciis and 

 Aniicd dmplexicaiilis grow in sand upon the 

 boulder strewn channel bottom:. 



Sdu JitdJi river bed- — Owing to the fact that 

 the descent in this valley is more gradual, typical 

 mud banks are found along the river sides. 



