HOW TO KNOW THE FRESH-WATER ALGAE 



289a (285) Filaments attached, uniseriate, branched. Fig. 204 



AUDOU1NELLA 



Fig. 204. Audouinella vioiacea (Kuetz.) 

 Hamel. a, habit of thallus; b, branches 

 in detail. 



A member of the Rhodophyta, this 

 species is nevertheless violet or gray- 

 green. The loosely branched filaments 

 are microscopic but may appear in tufts 

 of macroscopic proportions. The main 

 axial cells have disc-like or short ribbon- 

 like chromatophores. In size, form, and 

 habit of growth plants are easily mis- 

 taken for juvenile stages of Batracho- 

 sperum and if that genus is present in 

 the habitat it could be assumed that 

 Audouinella-\ike plants to be immature or so-called "Chantransia-stages" 

 of Batrachospermum rather than Audouinella. There is but 1 species 

 clearly defined in this country in fresh water and there is a disposition 

 on the part of some authorities to classify it under the genus Acrochae- 

 fium which is mostly marine. 



Figure 204 



289b Filaments attached, uniseriate, unbranched. Fig. 205 ... BANG1A 



ffiQQfflBBS 



Figure 205 



Fig. 205. Bangia iuscopurpurea (Dillw.) Lyngb., basal portion of fila- 

 ment. 



This is a simple, unbranched member of the Rhodophyta, greenish- 

 red or purplish in color. Filaments occur in tufts, sometimes dense, 

 attached to submerged stones and wood. Although most species of the 

 genus occur in salt water, this one is known from brackish or even 

 nearly fresh-water habitats. It may be ^expected in estuaries. 



290a (283) Chromatophores yellow, yellow-brown, or dark golden-brown, 

 rarely blue; plants motile or non-motile 341 



290b Chromatophores not yellow-brown or golden-brown 291 



127 



