DICTYOTACE^E. 61 



Genus XX. STILOPHORA. 



Eoot a small disc. Frond cylindrical, branched, traversed 

 by a cavity, which increases in size as the plant matures. 

 Fructification, convex, wart-like clusters of spores studded 

 over the surface of the frond. — Stilophoba, from the Greek 

 stile, a point, &X[A phoreo, to bear. 



The species of this genus are distributed on the shores 

 of the Atlantic Ocean^ and of the Mediterranean and 

 Baltic Seas. 



Stilophora rhizodes. Root-like Stilophora. 



Frond almost solid, much divided into narrow branches 

 bearing Scattered, forked branchlets. Fructification thickly 

 studded over the whole plant ; fibres of the sori simple ; 

 spores attached to them. 



Stilophora Lyngbyaei. Lyngbye's Stilophora. 



Frond tubular, with spreading branches forking from 

 wide rounded axils, and bearing scattered hair-like branch- 

 lets with very slender forked tips. Fructification arranged 

 round the frond in transverse lines at short intervals ; fibres 

 of the sori branched or forked, spores attached to them. 



Professor Harvey has figured both these species in the 

 ' Phycologia Britaunica/ but expresses a doubt whether 

 the differences between them do not depend on the rela- 

 tive depths of water in which they grow, ;S. rhizodes being 

 found within the tide-marks, while S. Lyngbyai always 

 grows in deep water. At the same time, he describes 

 and figures a considerable variation in the fructification 

 of the two plants to the effect that : in S. rhizodes the 

 fibres are simple, and the spores fixed to the surface of 

 the frond ; while in S. Lyngbyai the fibres are branched 

 or forked, and the spores are attached to them. Subse- 



