POLYSIPHONIA. 87 



divided in an alternate manner, bushy or feathery, the ultimate 

 ramuli exceedingly slender, fibrilliferous ; articulations of the 

 ramuli few-tubed, 2 4 times longer than broad. Harv. 

 Phyc. Brit. t. ccix. ; Wyatt, Alg. Danm. No. 176. Hutch- 

 insia violacea, Ag. Sp. Alg. ii. p. 76. 



On rocks and stones in the sea. Annual. Early summer. All round 

 the coast. Frond 6 8 inches high, with a principal stem, sometimes 

 much more slender than a hog's bristle, set from top to bottom with long, 

 alternate or irregular, quadrifarious branches of unequal length, but gra- 

 dually diminishing upwards, which again bear a second, third or fourth 

 series, gradually lessening in diameter and length, so that the plant has a 

 singularly feathery or finely bushy character, the ultimate ramuli exceed- 

 ingly slender, naked at base, with a few divisions near the summit, erecto- 

 patent, the tips splitting into byssoid fibres. Articulations of the stem 

 generally indistinct, irregularly tubed ; of ramuli 2 or 3-tubed, twice or 

 four times as long as broad. Colour a brownish red, often assuming a 

 fine purple in drying. Substance tender, gelatinoso-cartilaginous, quickly 

 decomposing in fresh water. Capsules ovate, sessile or shortly stalked ; 

 tetraspores large, binate or ternate, in the ramuli. The P. violacea of 

 ' Brit. Flora,' is a purple variety of P. nigrescens. 



13. P. Carmichaeliana, Harv. ; filaments tufted, rigid, 

 branched from the base; branches alternate, inarticulate, di- 

 varicating ; ramuli sub-dichotomous, very patent, their arti- 

 culations as long as broad. Harv. in Hook. Br. Fl. ii. p. 

 328. P. divaricata, Carm. (not of Ag.) 



Parasitical on Desmarestia aculeata at Appin, Capt. Carmichael. Fila- 

 ments tufted, 4 inches high, rigid, thicker than hogs' bristles ; branches 

 scattered, issuing at right angles, ramuli sparingly divided, patent and di- 

 varicating. Stem and principal branches longitudinally striated, inarticu- 

 late, or towards the apex having an obscure appearance of joints ; articu- 

 lations of the ramuli 2 4 striate, somewhat swollen at the joints. Colour 

 reddish brown, changing to black in drying, in which state it adheres very 

 imperfectly to paper. Of this plant I have only seen the single specimen 

 found by Capt. Carmichael, and preserved in Sir W. J. Hooker's herbarium. 



14. P.Jibrillosa, Dillw. ; pale straw colour ; stems inarti- 

 culate, robust, alternately branched ; branches patent, resem- 

 bling the stem, but somewhat jointed, sub-simple, thickly set 

 with very slender, finely divided, short ramuli, whose tips are 

 fibrilliferous ; articulations of the ramuli 2 or 3 tubed, rather 

 longer than broad. Hook. Br. Fl. ii. p. 334 ; Wyatt, Alg. 

 Danm. No. 136. 



On rocks and stones, and on Algae between tide-marks. Annual. 

 Summer. Common. Frond 6 10 inches long. Main stem sometimes 

 nearly half a line in diameter, always thicker than a bristle, attenuated up- 

 wards, furnished with several long, alternate or irregular, patent branches, 

 of nearly its own thickness, which sometimes issue horizontally, sometimes 

 are erecto-patent, but generally form considerable angles with the stem. 



