238 BRITISH SEA-WEEDS. {Ttliodosj-iermecB, 



drying. I preserve a very dark specimen as a memorial 

 of a pleasant half-hour's algologizing in the sweet bay of 

 Rosemai'kieej in E-oss- shire. 



Genus LXYII. GEACILAEIA, Greville. 



Gen. Char. Frond filiform, or rarely flat, carnoso-cartilnghioiis, 

 conthiiious, celhilar ; the central cells very large, empty, or full of 

 granular matter ; those of the surfiice minute, forming densely 

 packed, vertical filaments. Fructification of two kinds, on dis- 

 tinct individuals : 1, convex tubercles (coccidia) having a thick 

 pericarp, composed of radiating filaments, containing a mass of 

 minute spores on a central placenta ; 2, tetraspores imbedded in 

 the cells of the surface. — The name is from the Latin word sig- 

 nifying slender. — Ilarvey. 



1. Gracilahia erecta, Greville. 



Ilab. On sand-eovered rocks, near low-water mark. 

 Perennial. Fruiting in winter. Sidmouth and Torquay, 

 Mrs. Griffiths ; in Ireland, by ^Ir. AV. Thompson, Mr. D. 

 Moore, and Mr. IM'Calla ; in Orkney, by llev. T. II. Pol- 

 lexfen, Lieut. Thomas, and Dr. M'Bain. 



This curious httle plant is one of the numerous disco- 

 veries of Mrs. Griffiths. When in fructification it cannot 

 be mistaken for anything else, as the densely-clustered 



