Ser. MelanospermejE. Fam. Chordariea ?• 



Plate XCVIII. 



RALFSIA DEUSTA, Berk. 



Gen. Char. Frond coriaceo-crustaceous, fixed by its inferior surface, orbi- 

 cular, concentrically zoned; composed of densely packed, vertical, 

 simple filaments. Fructification ; depressed warts, scattered over the 

 upper surface, containing obovate spores fixed to the bases of vertical 

 filaments. Ralfsia (Berk.), — in honour of John Ralfs, Esq., of 

 Penzance, a most acute and accurate botanist, whose discoveries among 

 the minute Algse, especially the Diatomacea, have thrown great light 

 on that little known branch of botany. 



Ralfsia deusta. 



Ralfsia deusta, Berk, in Eng. Bot. Suppl. t. 2866. 



Hildenbrandtia rubra, Endl. 3rd Suppl. p. 26 {nee. syn. Berk.; nee. Menegh.). 



Cruoria verrucosa, Aresch. 



Padina? deusta, Hook. Br. El. vol. ii. p. 281. Harv.in Mack. El. Rib. 

 part 3. p. 178. Harv. Man. p. 31. 



Zonaria? deusta, Ag. Syn. p. 40. Ag. Sp. Alg. vol. i. p. 132. Ag. Syst. 

 p. 265. Lyngb. Hyd. Dan. p. 19. t. 5. 



Pucus fungularis, Oeder. El. Norv. vol. ii. p. 107- El. Dan. t. 420 (excl. 



syn. Lnperati.). 



Hab. Common on the rocky shores of the British Islands, between high- 

 water mark, and half-tide level ; from Orkney to Devonshire. Peren- 

 nial. Winter. 



Geogr. Distr. Atlantic shores of Europe from Iceland to Prance. Baltic Sea, 

 Aresch. Kamtschatka and Unalascha, Tilesius. 



Descr. Fronds spreading over the surface of rocks in crustaceous, lichenoid 

 patches, from one to six or more inches in diameter ; when young, orbicular, 

 but becoming very irregular in outline when old, marked, more or less evi- 

 dently, especially towards the margin, with concentric striae or bands, about 

 a fine asunder. The surface of the frond in young specimens is nearly fiat 

 and even, but in full grown individuals it is much corrugated, and covered 

 more or less with wart-like prominences ; and very old plants present an 

 exceedingly rugged surface, in which all traces of concentric striae are lost. 

 The structure of the frond is very dense and opake, but thin, vertical slices 

 exhibit an arrangement of the cellules into vertical elosly packed filaments, 

 strongly glued together. The fructification consists of scattered warts, com- 

 posed of vertical, easily separable filaments, to whose bases are attached 

 obovate, simple spores. Colour a dark, coffee-brown, becoming darker in 

 drying. Substance between leathery and crustaceous, flexible. 



This singular production more nearly resembles, to the naked 



