CLADOPHORA. 201 



of one articulation ; articulations twice as long as broad, 

 joints contracted. Dillw. t. 109 ; Hare. 1. c. p. '357 ; Wyatt, 

 Alg. Damn. No. 226 ; Harv. Phyc. Brit. t. cxxiv. 



On rocks, &c., near low-water mark ; rather rare. Bantry Bay, Miss 

 Hutchins, and various stations on the English and Irish coasts. Fila- 

 ments thicker than horse-hair, 6 8 inches long, flexuous, repeatedly di- 

 vided in an alternate manner; branches rather distant, spreading or divari- 

 cated, more or less furnished with short branchlets, having a few short, 

 secund ramuli along their upper faces. Colour deep glaucous green, "with 

 changeable tints when fresh, and under water appearing almost white,'' 

 (Miss Hutchins). Substance rigid and tough, more or less perfectly adher- 

 ing to paper. Joints uniform throughout the plant. Nearest C. pellucida 

 in texture, and C. diffusa in habit and character: from the latter it is not 

 always easy clearly to distinguish it. 



7. C. diffusa, Roth ; filaments sub-setaceous, rigid, dark 

 or full green, flexuous, much branched ; branches distant, 

 elongated, furnished towards the top with a few short, patent, 

 secund ramuli ; articulations 3 or 4 times longer than broad. 

 Dillw. t. 21 ; E. Bot. t. 2289 ; Harv. I. c. p. 358 ; Wyatt, 

 Alg. Danm. No. 144 ; Harv. Phyc. Brit. t. cxxx. 



On rocks, &c. in the sea, not uncommon. Southern shores of England 

 and Ireland : West of Ireland. Port Rush, Mr. Moore. Filaments 6 10 

 inches long, as thick as horse-hair, loosely tufted, generally so rigid as to 

 bristle out when removed from the water, but occasionally flaccid, very flex- 

 uous, distantly branched ; branches alternate, much divided, either bare of 

 ramuli, or furnished toward the end, or sometimes generally, with short, 

 secund branchlets. Joints 3 or 4 times longer than broad, nearly uniform 

 in all parts of the frond. Colour either grass-green or dark green. 



8. C. nuda, Harv. ; filaments sub-rigid, slender, very 

 straight, dull green or olivaceous (when dry), sparingly dt- 

 chotomous ; ramuli few and scattered, appressed, the upper- 

 most often opposite ; articulations many times longer than 

 broad. Harv. in Mack. Fl. Hib. in. p. 229. 



On basalt rocks, in the sea. Portstewart, Mr. D. Moore. Filaments 

 loosely tufted, 2 or 3 inches high, sparingly branched, very straight, set 

 with a few, scattered, very erect and appressed ramuli, the uppermost ones 

 often opposite, which makes the apices of the branches appear three-forked. 

 Articulations very long. This differs from any species with which I am 

 acquainted, but may, perhaps, be the C. aspera of Agardh, which in the 

 ' British Flora ' I have doubtfully referred to C. nigricans. To avoid con- 

 fusion, I think it better to give a new name to our present plant. In the 

 straight filaments and erect ramuli it resembles C. rupestris, but differs in 

 colour and in the great length of the joints. Perhaps it may be only a va- 

 riety of the latter. (A doubtful species 1 849). 



9. C. rupestris, Linn. ; filaments slender, rigid, dark 

 green, straight, tufted, bushy ; branches erect, crowded, 



