206 BRITISH SEA- WEEDS. \Jihodosperme(2, 



plumosa. " The true difference, however, must be placed 

 in the different structure of the ramuli, these being much 

 more simple in the present plant/^ The specific name, 

 sericea, expresses the soft and silky nature of the plant. 

 The colour is naturally a dark blackish-brown. It is greatly 

 improved in appearance when it assumes a pinky hue, and 

 this may be helped on by exposure to the air. It is then a 

 beauty. 



Family Till. GLOIOCLADIA. 



" Thus Nature varies : man, aud brutal beast. 

 And herbage gay, and scaly fishes mute, 

 And all the tribes of heaven, o'er many a sea. — 

 Search where thou wilt, each differs in his kind, 

 In form and figui*e differs." — Lucretius. 



Genus XLIV. CROUANIA, /. Aoardh. 



Gen. Char. Frond gelatinous, filiform, consisting of a jointed, 

 single-tubed filament, whose joints are clolbed with dense whorls 

 of minute multifid rarauli. Fructification of two kinds, on (hs- 

 tinct individuals : 1, " favellidia, subsolitary near the apex of the 

 ramuli, affixed to the base of the whorled ramelli, and covered 

 by them, containing, within a hyaline membranaceous perispore, 

 a subglobose mass of minute spores ;" 2, obovate tetraspores of 

 large size, atfixed to the bases of the ramidi. — The name is in 



