COLEOCH^ETE 419 



CONFERVOIDE.E 



COLEOCHLflETE SCUTATA, Brib 



Various species of Coleochcete are to be found growing 

 closely attached to the surface of submerged fresh-water 

 plants : they are green-coloured, and they attain such a 

 size as to be recognizable with the naked eye. The thallus 

 shows considerable variety of structure in different spe- 

 cies : thus it may appear as a flattened disc, one layer of 

 cells in thickness, closely attached to the surface of the 

 plant on which it grows (0. scutata) ; or it may consist 

 of a number of filaments branching in one plane only 

 (G. soluta) ; or it may take a hemispherical massive form, 

 being composed of closely packed, branching filaments 

 (C. pulvinata). Of these species 0. scutata is very 

 common, and is best adapted for observation. Having 

 ascertained that this plant is present (e.g. on the lower 

 surface of the lamina, or on the petiole of the Water 

 Lily) cut thin tangential sections, removing as little as 

 possible of the tissue of the leaf, but taking care not 

 to injure the Alga : mount in water, and examine under 

 a low power. Note 



1. The flattened discoid thallus, with more or less 

 irregular circular outline : it consists of one layer of 



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