Fig. 315. CLADOPHORA FRACTA. 



Colour. A dullish green; more or less light or dark. 

 Substance. Bigidj not adhering to paper. 



Character of Frond. Coarse jointed threads (^filaments) growing in long entangled 

 tufts in pools and ditches, where it rises at last to the surface, forming a 

 floating fleece. Filaments distantly branched; the lesser branches somewhat 

 forked, and spreading with very wide angles of branching {axils). Branchlets 

 few, alternate, or often secund. 



Joints. Very irregular in length. From three to six times as long as broad; diflPerent 

 lengths internaixed; filled with dense, full-green colouring matter, which, under 

 the microscope, is evidently formed into little grains {granules). 



Measurement. Indefinite. 



Fructification. As before, except that here and there, when well developed, the 

 zoospores fill the joints entirely, so that these become in fact a string of 

 fruit-cells (sporangia). This is usually observed about the middle of the 

 frond. 



Hahitat. In pools and salt-water ditches as well as in inland lakes. 



Fig. 316. RHIZOCLONIUM RIPARIUM. 



Colour. Light, bright yellow-green (sometimes darker); fading very dull in the 

 herbarium. 



Sulstance. Soft and delicately woolly; a peculiarity it retains in the herbarium. 



Character of Frond. Long, slender, jointed threads {filaments) lying flat on the sides 

 of rocks, clothing them with a fine close fleece. Filaments entangled; here 

 and there angularly bent, and sending out from the angles short, horizontal, 

 thorn-like, jointed fibres, which rarely lengthen into true branchlets containing 

 colouring matter (endochrome). 



Joints. From two to four times longer than broad. 



Measurement. From 1 to 3 inches long. 



Fructification. As before, in the genus Cladophora. 



Hahitat. Our coasts generally. (Filey). Oa broad faces of sandy rocks near high- 

 water mark. Not uncommon. 



Fig. 317. CONFERVA ARENICOLA. 



Colour. Pale yellow-green. 

 Substance. Soft; delicate. 



Character of Frond. Extremely fine, jointed threads {filaments) matted together; 

 creeping; forming a thin fleecy web on the ground. Filaments as slender as 

 human hair throughout; crisped; wavy; un branched. 



Joints. Once and a half as long as broad, when old enough to be observed; filled 

 with green colouring matter {endochrome)^ which at last contracts into a dark 

 mass in the centre, leaving the rest of the cell pellucid. When young, the 

 threads appear a uniform colour throughout, varied only by a few scattered 

 dots. ♦ • 



Measurement. Indefinite. 



Fructification. As before, in the genus Cladophora. 



HcMtat. "On the sandy margins of pools in a salt-marsh periodically flooded." Eev. 

 M. J. Berkeley. 



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