212 ALG^E RHODOSPERME^E. [Callithamnion. 



merits robust, cartilaginous, whorled throughout with imbri- 

 cated, incurved, many times dichotomous ramuli. Harv. in 

 Hook. Br. Fl v. ii. p. 337. Conf. equisetif. Dillw. t. 54. E. 

 Bot. t. 1479. 



On our western shores, common. Stems 6 12 inches high, very 

 robust and much branched. Branches tapering to a point. Fructi- 

 fication imperfectly known. 



2. G. simplicifilum, Ag. Slender Equiselum-like Griffithsia. 

 Filaments slender, irregularly branched, whorled with imbri- 

 cated, straight, once-forked ramuli. Ag. Sp. Alg. v. ii. p. 134. 



At Ardinairy Point, County of Wicklow, among rejectamenta ; and 

 growing very sparingly on rocks underneath Black Castle, Wicklow ; 

 W. H. Harvey. 4 8 inches high, slender, (compared with G. equi- 

 setifolia,) much branched. Branches long, mostly simple, the smaller 

 ones often bare of ramuli, the larger closely whorled with straight 

 branchlets forked at the base. This rare and beautiful species is 

 closely allied to the preceding, but is well distinguished by its straight 

 and nearly simple whorled ramuli. Fiuit unknown. 



3. G. multifida, Ag. Multifid Griffithsia. Filaments slen- 

 der, setaceous, distichously branched, whorled with dichoto- 

 mous, incurved ramuli; whorls distant; articulations of the 

 branches very long. Harv. in Hook. Br. Fl. v. ii. p. 338. 

 Conf. multifida, Huds. E. Bot. t. 1816. 



Rocky shores, not very uncommon. Bantry ; Miss Hutchins. 

 Kilkee and Miltown Malbay ; W. H. Harvey. 2 6 inches high, 

 slender. Capsules minute, scattered on the whorled ramuli. 



4. G. setacea, Ag. Setaceous Griffithsia. Filaments dicho- 

 tomous, setaceous, rigid, straight, naked ; axils very acute ; 

 articulations cylindrical, 5 6 times longer than broad. Harv. 

 in Hook. Br. Fl. v. ii. p. 338. Conf. setacea, Dillw. t. 82. E. 

 Bot. t. 1689. 



Sea-shores, not uncommon. 3 8 inches long, forming dense, often 

 inextricable tufts. Filaments slender, naked, throwing out occasional 

 creeping fibres. Involucres raised on lateral clavate peduncles. 



5. G. corallina) Ag. Coral-like Griffithsia. Filaments 

 thickish, gelatinous, dichotomous; axils patent; articulations 

 swollen upwards, 2 4 times longer than their diameter. Harv. 



in Hook. Br. FL v. ii. p. 338 Conf. corallina. Dillw. t. 98. 



E. Bot. t. 1815. 



Very rare. South Bull ; W. H. Harvey. Black rocks, Portrush ; 

 Mr. -D. Moore. 



55. CALLITHAMNION. Lyngb. Callithamnion. 



Frond filamentous; filaments articulate, mostly pinnate, one- 

 tubed; dissepiments hyaline. Fructification: 1. trisporous 

 capsules with hyaline pericarps, scattered on the ultimate 

 ramuli ; 2. roundish or lobed gelatinous receptacles (flavellce), 



