120 RHODYMENIACEiE. 



Hook. Br. Fl. ii. p. 293 ; Wyatt, Alg. Danm. No. 20 ; Harv. 

 Phijc. Brit. t. xHv. Fucus coccineus, E. Bot. t. 1342. 



On rocks and Algae, common evei^ where. Perennial. Summer and au- 

 tumn. — Root librous. Fronds tufted, 2 — 12 inches long-, excessively branch- 

 ed and bushy, compressed, two-edged, very narrow, main stems half a line in 

 diameter, irregularly divided, thickly set with patent alternate branches, 

 which are throughout furnished with short distichous ramuli, which are either 

 simple and subulate, or bearing a second and third series of similar subu- 

 late ramuli from their inner face, the compound ramuli resembling small 

 combs. Tubercles solitary, sessile on the edge of the upper branches ; 

 tetraspores oblong, transversely divided into several joints, contained in 

 little branching receptacles borne by the ramuli. 



Order XL RHODYMENIACEiE. 



SphaerococcoideaB, J. Ag. Alg. Meclit. p. 148. Endl. 3rd 

 Suppl. p. 55, Sphserococceae, Liiidl. Veg. Kingd. p. 25. 

 Part of Gasterocarpeae, Sphaerococcoidese, and Chondrieae, 

 Bne. Class, p. 64—65. 



Diagnosis. — Purplish or blood-red sea-weeds, with an ex- 

 panded or filiform, inarticulate frond, composed of polygonal 

 cells ; occasionally traversed by a fibrous axis. Superficial 

 cells minute, irregularly packed, or rarely disposed in fila- 

 mentous series. Fructijication double : 1, Conceptacles 

 {coccidia) external or half immersed, globose or hemispheri- 

 cal, imperforate, containing beneath a thick pericarp a mass 

 of spores affixed to a central placenta : 2, Tetraspo-res either 

 dispersed through the whole frond, or collected in indefinite, 

 cloudy patches. 



Natural Character. — Root disk-like or branched^ some- 

 times much matted. Frond very variable in habit and 

 colour, either leafy or filiform and much branched, never ar- 

 ticulate ; in some an intense scarlet, in some crimson, in 

 others brown-red or purple, usually growing somewhat darker 

 in drying. The leaf-like expansions of the frond are very 

 rarely symmetrical ; and never (except in Stenogramme, 

 which is scarcely a real exception) furnished with well- 

 defined midribs, but in several the central portion is some- 

 what thickened and traversed by a bundle of closely packed 

 filaments which constitute an internal rib. Such a rib occurs 

 in several of the filiform species, where it is only discoverable 

 on dissection. The frond is commonly dichotomously or 



