Fig. 57. MESOGLOIA VIRESCENS. 



Colour. Olive-green; often yellowish. 



Substance. Soft^ gelatinous, slimy; loose as if likely to tumble to pieces. 



Character of Frond. Cylindrical, slender, excessively branched. Branches 

 long, spreading, on each side a stem; irregularly alternate; furnished 

 with numbers of short branchlets. The whole frond looking hairy 

 when examined; partly from its loose structure; partly from the colour- 

 less cobweb-like hairs with which it is clothed. 



Measurement. From 8 to 12 inches long. About the thickness of a crow's 

 quill. 



Fructification. Minute seeds [spores) concealed in the substance of the frond. 



Habitat. Our coasts generally. On rocks, stones, and algae, at half -tide 

 level. Common. --^^ 



The structure of tlie Mesogloias is on the model of that of a bottle brush; 

 namely, a stalk surrounded with bristles. So the Mesogloias have a firm, in- 

 ternal stalk {axis), with radiating filaments surrounding it. 'i hese filaments, 

 however, being delicate, and invested with gelatine, the plants are all slimy- 

 feeling to the touch. 



Fig. 58. CLADOSTEPHUS VERTICILLATUS. 



Colour. A dull green, inclined to olive: darker and browner when old. 

 Substcmce, Rigid; harsh. 



Character of Frond. Bushy. Branches slender, cylindrical; partly forked 

 [dichotomoiis), partly alternate or opposite, on each side a stem. Stem 

 and branches frilled {whorled) at short intervals with short, incurved 

 branchlets; which q,vq jointed, that is, composed of cells joined together 

 in a line. Many of these drop off during winter. 



Measurement. From 3 to 9 inches high. 



Fructification. Oval seeds [spores) borne on small branchlets which grow 

 irregularly on the frond after the summer frills [whorls) die off. 



Habitat. Our coasts generally, except the north-east. On rocks and 

 corallines. 



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