116 GELIDIACE^. v. 



cylindrical, of a firm, tenacious substance and densely compacted structure, and 

 Avhen dry is very rigid, almost horny. Wlien growing, the colour is a purplish red 

 uf o-reater or less intensity. On exposure to the air or immersion in fresh water 

 and subsequent drying, this purple changes through various brilliant tints of red, 

 orange and yellow to a waxy or glassy white, retaining a polished surface even 

 when completely bleached. Both kinds of fructification are lodged in the smaller 

 ramuli or pinnules, at some distance below their extremity. The tetrasjwres form 

 little sori, or cloudy patches, and generally occur in slightly expanded, obtuse 

 ramuli, sometimes in the ordinaiy pinnules and sometimes in minute accessory or 

 special processes of the rachis. The conceptacles whose remarkable structure was 

 first, I believe, correctly described by Prof. J. Agardh (Advers. p. 42) are very 

 curious and beautiful microscopic objects. They are formed in the substance of the 

 fertile ramulus, rising towards each of its flat surfaces like little hollow blisters, 

 opposite each other, leaving as a dissepiment between them the flattened axial 

 stratum of the branchlet ; so that it would be more correct to describe them as 

 binate, opposite conceptacles, than as a two-celled conceptacle, which is the appa- 

 rent structure. 



1. Gelidium corneum, Lamour.; frond two edged, flat or sub-terete, purplish 

 red, two to four times pinnated ; pinnulse narrowed at base, linear, entire, obtuse, 

 rarely subacute, those containing the tetraspores club-shaped or obovate, very 

 obtuse ; conceptacles below the apex of the ramulus. Harv. Phyc. Brit. t. 53. /. Ag. 

 Sp. Alg. 2, p. 469. Kiitz. Sp. Alg. p. 764. Fucus corneus, Huds. — Turn. Hist, 

 i. 257. E. Bot. t. 1970. 



Hab. Pacific and Atlantic Coasts. Russian America, Postells and Ruprecht. 

 California, Dr. Coulter, Capt. Pike. Portland, Maine, Capt. Pike (54). Red Hook, 

 New York Bay, Mr. Hooper, Mr. Walters, &c. Sullivan's Island, Charleston, Prof. 

 Gibbes, W. H. H. (v. v.) 



A most variable plant. Dr. Coulter's Californian specimens are three or four 

 inches high, broadly ovate in outline, the lower branches being long, the upper 

 gradually shorter, very densely set and about three times pinnated ; the pinnas and 

 pinnules patent, tapering to the base, very blunt at the apices, either rounded or 

 subtruncate. The colour is a dark brownish purple. The specimens from New 

 York and Maine are very much smaller, rarely more than an inch and half high, 

 scarcely thicker than hog's bristle, less strongly compressed and more flabelliform 

 in outline, the frond and its principal branches being naked below, and pinnated 

 only above the middle. The Charleston specimens are very similar, but less decom- 

 pound and the ramuli are not so blunt. These latter are in conceptacular fruit, 

 the conceptacle lodged about the middle of the pinnules, or occasionally even in 

 one of the pinnae toward the base. 



