92 rOLYSII'HONIA. 



23. P. furcellata, Ag. ; filaments elongated, tufted, en- 

 tangled, flexuous, repeatedly and closely dichotomous ; axils 

 broad, rounded ; raniuli erect, their points hooked in ; middle 

 articulations 3 — 5 times longer than broad ; tubes about 

 eight. Harv. in Hook. Br. Fl. ii. p. 332 ; Harv. Phyc. 

 Brit. t. vii. Hutchinsia furcellata, Ag. Sp. Alg. ii. p. 91. 



Floating in the sea, at vSidmoutb ; Mrs. Griffiths and Miss Cutler. 

 Dredged in Torbay, Mrs. Griffiths. Carrickferous, Mr. M'Calla. Round- 

 stone, W. H. H. — Filaments slender, 5 or 6 inches long, much entangled, 

 and excessively branched, flexuous, the divisions dichotomous, very close 

 towards the extremities. Articulations with several slender striae, which 

 sometimes cross each other, variable in length ; those of the larger branches 

 3 — 5 times, of the ramuli about twice as long as broad. Colour, when re- 

 cent, "a bright brick-red" {Mrs. Griffiths), changing in the herbarium to a 

 deep umber-brown. Substance, according to the same lady, "at first firm, 

 but becoming flaccid immediately." Cajjsules unknown. A most distinct 

 and beautiful species. 



24. P. fastigiata, Roth. ; filaments rigid, setaceous, of 

 equal diameter throughout, forming globular tufts, many 

 times dichotomous ; axils patent ; articulations shorter than 

 their diameter, multi- striate ; siphons sixteen to eighteen. 

 Hook. Br. Fl. ii. p. 333; Wyalt, Alg. Damn. No. 177. 

 Conf. polymorpha, E. Bot. t. 1764. 



Parasitical on Fucus nodosus and vesiculosus, especially the former ; very 

 common. — Filaments 2 — 4 inches long, rigid, forming globose, dense, bushy 

 tufts of a brown or yellowish colour. The above characters abundantly 

 distinguish this from every other species. 



25. P. parasitica, Huds. ; slender, rigid, full-red, alter- 

 nately branched, distichous ; branches bi-tripinnate ; pinnae 

 alternate, erect, awl-shaped ; articulations about as long as 

 broad, three-tubed ; siphons eight ; ceraraidia ovate, on 

 short stalks. Hook. Br. Fl. ii. p. 330 ; Harv. Phyc. Brit. t. 

 cxlvii. ; Wyatt, Alg. Damn. No. 175. Conf. parasitica, E. 

 Bot. t. 1429. 



On the larger Alga, and (more frequently) on nullipores at the extreme 

 limit of low- water, not uncommon on many of our coasts, but nowhere very 

 abundant. — Stems half an inch to an inch and a half high, somewhat com- 

 pressed, rigid, simple, dislichously branched; branches alternate, short 

 below, longer above, from two lines to three-fourths of an inch long, pin- 

 nated or bipinnated with awl-shaped, simple, acute, erecto-patent ramuli. 

 Articulations of the branches about as long as broad, of the ramuli much 

 shorter, marked with 3 or 4 broad tubes, with wide, transparent intervals. 

 Substance cartilaginous, imperfectly adhering to paper. Colour rose-red, 

 becoming brownish when dried. 



26. P. byssoidcs, Good, and Woodvv. ; stems rigid, seta- 

 ceous, cartilaginous, alternately or distichously branched ; 



