CRYPTOGAMIA ALG^E. 231 



Fucus crispus, Eng. BoL t. 2285. F. ceranoides y LIGHTF. Scot. 

 913. Spharococcus crispus, HOOK. Scot. ii. 102. 



Hob. On rocks very common, in tufts from 2 to 4 inches 



high. -4 



Very variable in form and colour. It is very plentiful in 

 the pools left by the recess of the tide, but our finest spe- 

 cimens were taken from the stems of Laminaria digitata. 

 The frond is often partially iridescent. In Ireland, as I 

 am informed by my friend W. C. TREVELYAN, Esq. a sort 

 of isinglass is prepared in considerable quantities from this 

 sea-weed. On boiling with water, it forms a strong trans- 

 parent jelly, which, with the admixture of lemon and 

 sugar, makes an agreeable medicine in ordinary coughs, 

 and probably more efficacious than the usual demulcents, 

 from the small portion of iodine which the mixture may 

 contain. It is sometimes sold in the apothecaries' shops as 

 a substitute for Iceland moss (Cetraria islandica). NEILL. 



133. GELIDIUM. 



1. G. corneum, frond between cartilaginous and corneus, com- 

 pressed, repeatedly pinnated, pinnse and pinnulre spreading, long, 

 very thin, acute and irregularly divided ; capsules spherical, im- 

 mersed in the extremities of the ramuli. GREV. Alg. Brit. 143. 

 Fucus nereideus, LIGHTF. Scot. 956. Sphcerococcus corneus, HOOK. 

 Scot. ii. 104. 



Hao. Black rocks near Bamburgh, Dr Greville. If 



134. LAWRENCIA. 



1. L. pinnatifida, frond cartilaginous, compressed, branched; 

 branches pinnatifid, obtuse and bluntly toothed. GREV. Alg. 

 Brit. 108. Fucus pinnatifidus, LIGHTF. Scot. 953. WITH. iv. 119. 

 NEILL in Edin. Encycl. x. 22. Chondria pinnatifida^ HOOK. Scot. 

 ii. 105. 



Hab. On rocks, very common. Summer. 



From 1 to 3 inches high, purplish-brown, frequently growing 

 on the sides of rocks in a somewhat imbricate manner. A 

 variety of a yellowish colour, with a cylindrical frond, the 

 branches simple, short and crowded towards the summit, is 

 likewise abundant on our coast. This grows in dense erect 

 tufts in shallow pools much exposed to the sun, while the 



