Yaak River at Whitetail Campground. This sample contained moss. Diatom biomass 

 was composed mostly of the polysaccharide stalks of a large Cymbella species. T\\o species of 

 Oedogoniiim were present. 



Yaak River at Sylvan ite. This sample consisted of a large gray mass ("dirty cotton 

 ball") that was composed mostly of the polysaccharide stalks of the diatom Didymosphenia 

 geminata. 



West Fork Yaak River. This sample was \irtually free of sediment. Both the 

 chantransia stage and the usual \egetative stage of Batrachospermum were included in the 

 sample. The Ulothrix in this sample was not U. zonata. 



Non-Diatom Algae (Table 3) 



Yaak River above East Fork. Diatoms were the most abundant group of algae at this 

 site, followed by several genera of green algae. Stigeoclonium, a pollution tolerant and branched 

 filamentous green alga, was frequent here and ranked second after diatoms in biovolume. The 

 encrusting brown alga Heribaudiella ranked seventh in biovolume here. This alga is typically 

 found only in cold and clean mountain streams. Altogether, this site supported nine genera of 

 non-diatom algae representing two algal divisions. This was the only site where cyanobacteria 

 (blue-green algae) \%ere absent. 



Yaak River at Whitetail Campground. Diatoms dominated the sample from this site, 

 followed by 9 genera of green algae. The most common green algae were Spirogyra ("pond 

 szM.vci"'), Scenedesmus, Oedogoniiim, Chaetophora, and Cosmarium. The only cyanobacterium 

 was Merismopedia, which was rare. This site supported 10 genera of non-diatom algae 

 representing two algal divisions. 



Yaak River at Sylvanite. Diatoms also dominated the sample from this site, followed in 

 biovolume rank by the pollution tolerant Stigeoclonium, which was abundant. A few other green 



