CLADOPHORA. 1 99 



chiefly marine. A few, here omitted, inhabit clear, fresh- 

 water streams. 



1. C. Brou'nii, Dillw. ; filaments forming dense, cushion- 

 like tufts, erect, rigid, flexuous, elastic, slightly branched ; 

 branches few, long, sub-simple, secund ; axils acute, articu- 

 lations 4 or 5 times longer than broad, the lower ones thick- 

 ened upwards, the upper cylindrical. Harv. I. c. p. 356 ; 

 Dillw. Suppl. t. D. ; E. Sot. t. 2879 ; Harv. Phyc. Brit. t. 

 xxx.; Wyatt, Alg. Danm. No. 225. C. pulvinata, Brown, 

 MS. 



On wet rocks in a cave near Dunree, North of Ireland, R. Brown, Esq. 

 On shady rocks at the entrance of a small cave beyond Black Castle, Wick- 

 low, where it is exposed to the dripping of fresh water, and the occasional 

 overflow of the sea. Cornwall Coast, near Land's End, Mr. Ralfs. This 

 forms exceedingly dense, very rigid, tufts, of a black-green colour when 

 growing, but, on having the water expressed, and being held to the light, 

 exhibits a beautiful yellow-green tint. Filaments so matted together that 

 it is difficult to separate a single thread. They appear to originate in a 

 mass of creeping, branched, densely matted fibres, which form the base of 

 the tufts. They are erect, from half an inch to an inch high, flexuous, very 

 rigid and elastic ; the branches few and nearly simple, almost always 

 secund, very erect. A very curious and distinct plant, having, to the naked 

 eye, a good deal the appearance of Vaucheria terrestris, but totally differ- 

 ent in structure. It is perhaps allied to C. (egagropila. I have examined 

 a specimen from Mr. Brown in the late Mr. Templetoris herbarium, and 

 find it agree in every respect with my Wicklow plant. 



2. C. repens y J. Ag. ; forming dense, cushion-shaped or 

 globular tufts ; filaments short, capillary, rigid, densely mat- 

 ted together, rising from root-like fibres, slightly branched ; 

 branches erect, sub-simple, or forked, naked, or with a few 

 distant, secund ramuli; articulations cylindrical, very long, 

 (ten to twenty times as long as their diameter). Harv. Phyc. 

 Brit. t. ccxxxvi. 



Thrown on shore after a gale. Annual? Summer. Jersey, very rare, 

 Miss Turner. Tufts an inch or two in diameter, and about half an inch 

 thick, composed of innumerable, slender filaments densely matted together. 

 The habit is very similar to that of C. firownii, but the articulations are of 

 much greater length, and of a different form. This species is also a native 

 of the north coast of France, and of the Mediterranean sea. 



3. C. pellucida, Huds. ; filaments cartilaginous, rigid, 

 erect, bright green ; di-trichotomous, the axils very acute, 

 branches erect; articulations many times longer than broad. 

 Harv. 1. c. p. 357 ; Wyatt, Alg. Danm. No. 193 ; E. Bot. t. 

 1716; Harv. Phyc. Brit. t. clxxiv. 



On rocks near low-water mark. Yarmouth, Sir W. J. Hooker. South 

 of England. Several places in Ireland ; very fine in Belfast Lough, Mr. 



