134 CRYPTONEMIACEjE. 



Europe, where it produces fruit abundantly, and where the 

 branches are very much broader than they are in English 

 specimens. This plant is very closely allied to G. Chauvini 

 and G. Chamissoi of South America, species of larger size, 

 some of whose forms are with difficulty distinguished from 

 some broad states of G. Teedii from the Adriatic. Several of 

 the southern Gigartina have flat fronds two or three feet long 

 and or two feet broad, resembling gigantic Iridaea, but hav- 

 ing a structure identical with that of the filiform kinds. 



Many of the Cryptonemiacese may be used as food ; and 

 among others, the Carrageen (Chondrus crispus) has been 

 largely employed both as an esculent, in the shape of jellies 

 and blancmanges, and for the manufacture of size for calico 

 printers. It has also been recommended for fattening calves, 

 being boiled to a jelly and then mixed with milk. If boiled 

 in water, and thickened with refuse potatoes or meal, it forms 

 no bad provender for swine. It is nearly tasteless, and boils 

 down to a strong jelly. Gigartina mamillosa has similar pro- 

 perties, and is often substituted for Chondrus. Iridcea edulis, 

 notwithstanding its specific name, is much less frequently 

 made use of, but in some parts of England and Scotland it 

 is said to be eaten by the fishermen, either raw, or after hav- 

 ing been pinched between hot irons or fried ; and is said to 

 taste like roasted oysters. 



SYNOPSIS OF THE BRITISH GENERA. 



Sub-order 1. COCCOCARPE.E. Frond solid, dense, cartilagi- 

 nous or horny. Favellidia contained in semi-external or 

 external tubercles, or swellings of the frond. 



I. GRATELOUPIA. Frond pinnated, flat, narrow, membra- 



naceo-cartilaginous, of very dense structure. Favel- 

 lidia immersed in the branches, communicating with 

 the surface by a pore. Tetraspores scattered. [Plate 



17, A.] 



II. GELIDIUM. Frond pinnated, compressed, narrow, 



horny, of very dense structure. Favellidia immersed 

 in swollen ramuli. Tetraspores forming subdefined 

 sori in the ramuli. [Plate 17, B.] 



III. GIGARTINA. Frond cartilaginous, cylindrical or com- 

 pressed, its flesh composed of anastomosing filaments, 



