Callithamnion.] ALGJE RHODOSPERMEJE. 213 



containing large granules, seated on the main branches. 

 Name ; /caXos, beautiful, and Oapvos, a shrub. A most diffi- 

 cult genus, forming endless species and varieties. In the 

 following descriptions, the term "plumula" is applied to a 

 penultinate-branchlet, when pinnate or bipinnate. 



A. filaments erect, much branched, not rising from creeping 



fibres. 



a. Ramuli opposite. 



1. C. Plumula, Lyngb. Pectinated Callithamnion. Ramuli 

 short, opposite, recurved, pectinated on their inner margins. 

 Harv. in Hook. Br. Fl. v. ii. p. 339. Conf. Plumula, Dillw. 

 t. 50. Conf. Turneri, E. Bot. t. 1637. (not t. 2339.) 



Sea-shores, not common. Bantry ; Miss Hutchins. Killiney ; 

 W. H. Harvey. Black rocks, Portrush ; Mr. D. Moore. 2 -4 

 inches high, much branched, fine rose-red. This is well marked by its 

 very peculiar and symmetrical ramuli. 



2. C. pumilum, Harv. Slender Cruciate Callithamnion. 

 Filaments sparingly branched ; ramuli very short, opposite, 

 pinnated ; pinnae abreviated, very erect ; main articulations* 

 2 3 times longer than broad. Harv. in Hook. Br. Fl. v. ii. 

 p. 339. 



Very rare. Miltown Malbay ; W. H. Harvey. About an inch 

 high, distantly branched, forming small tufts ; each articulation fur- 

 nished with a pair of very short pinnated ramuli. 



b. Ramuli alternate ; pinnate or dichotomous. 



1. Secondary branches pinnate or plumulate. 



\ Main stems inarticulate. 



3. C. Arbuscula, Lyngb. Shrubby Callithamniom. Stems 

 naked below, robust, cartilaginous ; main branches set with 

 short branchlets, which are again thickly clothed with minute, 

 imbricated, oblong plumules ; ultimate pinnules simple or forked, 

 recurved or divaricating, attenuate, acute ; capsules very nu- 

 merous, lining the inner faces of the pinnules. Harv. in Hook. 

 Br. Fl. v. ii. p. 340. Conf. Arbusc^lla, JR. Brown. Dillw. 

 t. 85. E. Bot. t. 1916? Dasya Arbuscula and spongiosa, Ag. 



On rocks and shells, on our northern and western shores, very com- 

 mon ; but not found, that I am aware, on the east coast. 3 5 inches 



* By main articulations will be understood, the articulations of the stem or 

 branches, in contra- distinction to those of the ramuii. 



