176 CALLITHAMNION. 



late ; stem cartilaginous, sub-simple, setaceous, somewhat 

 opake, veiny, set with sub-quadrifarious, lateral branches, of- 

 ten furnished with a second series ; penultimate branches 

 pellucidly jointed, slender, elongate, set with short, alternate, 

 very erect, level-topped plumules, the lowermost of which 

 are most simple ; ramuli erect, subulate, not narrowed at 

 base, gradually tapering to a fine point, their articulations 

 twice as long as broad, cylindrical ; tetraspores minute, oval, 

 near the tips of the ramuli. Harv. Phyc. Brit. t. cxxxvii. 

 C. granulatum, Harv. in Hook. Br. Fl. ii. p. 334 (not of 

 Ag.}. C. Harveyanum, J. Ag. in Linn. xv. p. 45. 



Parasitical on Algae, near low-water mark ; frequent. A more slender 

 plant than the preceding, with longer articulations in the stem, but chiefly 

 distinguished by the different form of the ultimate ramuli. In C. tetrago- 

 num the ramuli are mucronate, or suddenly tapering at the point; here 

 they are subulate, tapering from the very base. Still, this character may 

 possibly be variable. 



12. C.teiricum, Dillw.; rigid; branches densely ramulose, 

 shaggy below, plumulate above ; plumules crowded, quadri- 

 farious, simply pinnate ; pinnae acute, tapering to the base, 

 erecto-patent; articulations 2 or 3 times longer than broad ; 

 tetraspores elliptical, minute, on short, lateral processes of the 

 pinnules. Harv. in Hook. Br. Fl. ii. p. 342 ; Wyatt, Alg. 

 Damn. No. 141 ; Harv. Phyc. Brit. t. clxxxviii. Conf. 

 tetrica, E. Bot. t. 1915. 



In the sea, generally growing on the perpendicular faces of rocks, at half- 

 tide level. Perennial. Common on the rocky coasts of England, and of 

 the west and south of Ireland. Fronds 2 8 inches long, divided into se- 

 veral principal branches, closely covered with long, peculiarly straight and 

 rigid, pinnated ramuli, mixed with simple or irregularly branched ones ; the 

 the branches having a coarse, ropy character. Plumules simply pinnated, 

 the pinnae erecto-patent, contracted at base, attenuated upwards. Colour 

 a dull brownish-red. Substance more rigid than in most, imperfectly ad- 

 hering to paper, very fragile if moistened after having once been dried. 

 Articulations uniformly about once and a half as long as broad. Tetras- 

 pores ] 3 on each lateral process. Favellce generally in pairs, minute, 

 seated on the pinnae, and nearly terminal. 



13. C. Hookeri, Dillw.; stem setaceous, inarticulate or 

 spuriously jointed, simple, set with one or more series of al- 

 ternate, spreading, flexuous branches, the smaller of which 

 are jointed ; all furnished with very patent, pinnated ramuli 

 or plumules ; ultimate pinnules divaricating, their joints 

 twice or thrice as long as broad ; tetraspores along the inner 

 faces of the ramuli near the base. Harv. Phyc. Brit. t. 

 cclxxix. ; Harv. in Hook. Br. Fl. ii. p.. 341. Conf. Hookeri, 



