RED ALG^Z. 185 



white. The frond is composed of cylindrical fila- 

 ments, a trifle flattened, the main stem branching 

 from its edges, as do also the principal branches. 

 The whole plant is built up of small stony, some- 

 what wedge-shaped joints, a trifle the widest at the 

 top, all the branches and branchlets spring from 

 the top of the joints directly below. It generally 

 refuses to adhere, but may be fastened down with 

 straps of gummed paper. 



Order.— GELWIEJ2. 



Genus. — GEL1DIUM* Lam. 



One species of this is a native of both shores, 

 and the others of the Pacific alone. They are nar- 

 row, compressed, rarely quite cylindrical plants, of a 

 firm, tenacious substance, and, when dry, quite rigid 

 and horny. They are pinnately branched, and the 

 branching is mostly in one plane. 



Gelidium corneum, Lam. 



This is a most variable plant. A typical form, 

 such as we figure, in Plate XIII, will not very fre- 

 quently be found. But every plant will be but a 

 variation on that theme. Plants of this species on 



* Gelidium = Ice-like or jelly-like. 



