62 BRITISH SEA-WEEDS. 



quently, however, he appears to have altered this opi- 

 nion, and in his ' Nereis Boreali-Americana' he describes 

 and figures the spores of S. rhizodes as being attaohed 

 to the bases of the fibres. 



Genus XXI. DICTYOSIPHQN. 



Root a small disc. Frond thread-like, tubular, branched. 

 Fructification, naked spores scattered over the frond either 

 singly or in clusters. — Dictyosiphon, from the Greek 

 dictuon, a net. and siphon, a tube. 



Dictyosiphon fceniculacens. Fennel Dictyosiphon. 



Frond very much divided into long, slender branches, 

 bearing awl-shaped branchlets. 



AYhen young the fronds of this species are of a green- 

 ish-olive colour, and are covered throughout with jointed 

 fibres; mature specimens are brown. This plant is an- 

 nual, and grows abundantly in tide pools during spring 

 and summer. 



Genus XXII. STBIAKIA. 



"Root a small disc. Frond tubular, of thin substance, 

 branched. Fructification small clusters of spores arranged 

 in zones round all parts of the frond. — From the Greek 

 strix, or Latin stria, a fluting, in allusion to the arrangement 

 of the spores in transverse lines. 



Striaria attenuata. Tapering Striaria. 



Fronds much branched, growing in tufts, three inches 

 to a foot high; branches and branchlets nearly opposite, 

 tapering at each end. 



This species delights in quiet, sheltered situations, and 

 grows at a considerable depth. It is annual, and in 

 perfection in summer. 



