64 MYRIOTRICHIA. 



minute, papillaeform ramuli. Wyatt, Aly. Danm. No. 304 ; 

 Harv. Phyc. Brit. i. clvi. 



Parasitical on Chorda lomentaria and Asperococcus echinatv^, sometimes 

 accompanying the preceding. — Fronds an inch or more in length, very 

 slender, straight, or more usually flexuous, often twisted or several bundled 

 together into rope-like tufts ; the stem quite simple, at intervals appearing 

 thickened into dark-coloured knobs, which are found, under the higher 

 powers of the microscope, to consist of very dense, minute, papillaeform 

 ramuli, from whose apices issue, as in the last species, long, simple, 

 colourless fibres. The intervals between the knohs or papillated portions 

 are cylindrical and jointed, the joints being rather shorter than broad. 

 This is a much taller and slenderer plant than M. clavcBformis, and easily 

 distinguished by its interrupted ramuli, which are besides very much 

 shorter than in that species, and do not increase in length toward the up- 

 per part of the stem. I believe it to be a much more common plant than 

 M. davceformis, and perhaps some of the stations assigned to that species 

 belong to this. 



Sub-class II. 



RHODOSPERME.E or CERAMIALES. 



Harv. in Mack. Fl. Hib. part iii. p. 185 (1 836). Floride.e, 

 J. Ag. Alg. Medit. p. 54 (1842). Floridese, with part of Con- 

 fervoidese and Fucoideae, Ag. Syst. p. xxxiii. (1824). Flori- 

 deae, Gastrocarpeae, Spongiocavpeae and Furcellarieae, Grev. 

 Alg. Brit. pp. 66, 68, 71, 157. Choristosporeae, Dne. Ess. 

 p. 52 (1842). Ceramiaceae, Lindl. Veg. King. p. 23. Hete- 

 rocarpeae, Kiiiz. Phyc. Gen. p. 369. 



Diagnosis. — Plants rosy red, or purple, rarely brown-red 

 or greenish red. Fructijication of two kinds, dicEcious, al- 

 ways formed on separate individuals : 1, spores contained 

 either in external or immersed conceptacles, or densely ag- 

 gregated together and dispersed in masses through the sub- 

 stance of the frond ; 2, spores (called tetraspores) red or 

 purple, either external or immersed in the frond, rarely con- 

 tained in proper conceptacles ; each spore enveloped in a 

 pellucid skin \perispore), and at maturity separating into four 

 sporules. Antheridia (not observed in all) filled with yellow 

 corpuscles. Marine, with one or two exceptions. 



