144 BRITISH SEA-WEEDS. \_Mdanosperme(c, 



Root minutely scutate, naked, rructification, solitary or aggre- 

 gated naked spores, scattered irregularly over the surface. — The 

 name is from two Greek words, signifying net-tcork and a tube, 

 the frond being tubular and reticulated. — Greville. 



1. DiCTYOSipno>; ra^xicuLACEus, Grev. 



Hab. lu the sea, on Chorda filiuji and other Algae. An- 

 nual. Spring and summer. Anglesea, Dillenius ; Cornwall, 

 Hudson ; Ireland, Miss Hutchins, Dr. Drunnnond; Frith of 

 Forth, Dr. Greville. On the Ayrshire coast, very common. 



It resembles in appearance Dlchloria or Desmaresiia 

 viridis. Within the tube the surface is lined with pellucid 

 oblong cellules. Colour, when young, pale yellow or olive- 

 green ; when old, it is of a rusty-brow n colour, and the 

 plant is then several feet long, and has a coarse appearance. 



Genus XXI. STRIARIA, Greville. 



Gen. Char. Frond filiform, tubular, continuous, membrana- 

 ceous, branched. Root naked and scutate. Fructification, 

 groups of roundish seeds forming transverse lines. — The name 

 is from the transverse stria, formed by the lines of fructification. 



1. Striaria attenuata, Greville. (Plate II. fig. 8.) 

 Ilab. Parasitical on the smaller Alga?, generally beyond 

 tide range. Found by Dr. Greville in Bute. The branches 



