176 CALLITHAMNION. 



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

 opake, veiny, set with sub-quadiifarious, 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 Harieyanum, J. Ag. in Linn. xv. p. 45. 



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

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

 distinguished hy the difl'erent form of the ultimate ramuli. In C. tetrago- 

 num i\\e 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. Cteiricum,T>\\\\\.; rigid; branches densely ramulose, 

 shaggy below, plimiulate above ; plumules crowded, quadri- 

 farious, simply pinnate ; pinna) acute, tapering to the base, 

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

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

 ):)innules. Harr. in Hook. Br. Fl. ii. p. 342 ; IT'ipfH, Alg. 

 Danni. No. 141 ; Harv. Vhyc. Brit. t. clxxxviii. Cotif. 

 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. — Fr<mds2 — 8 inches long, divided into se- 

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

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

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

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

 a dull brovvnish-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 arid a half as long as broad. Tetras- 

 pores 1 — 3 on each lateral process. Favellce generally in pairs, minute, 

 seated on the piunaR, and nearly terminal. 



13. C. Hooker i, Dillw. ; stem setaceous, inarticulate or 

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

 ternate, sjiroading, flexuous branches, the smaller of which 

 are jointed ; all furnished with very patent, pinnated ramuli 

 or ])lumulcs ; 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. Bril. t. 

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



