120 RHODYMENIACE.E. 



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

 Phyc. Brit. t. xliv. Fucus coccineus, E. Bot. t. 1342. 



On rocks and Algae, common everywhere. Perennial. Summer and au- 

 tumn. Root&brous. Fronds tufted, 2 12 inches long, excessively br*anch- 

 ed and busby, 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 ram uli, 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 RHODYMENIACE^. 



Sphasrococcoideae, J. Ag. Alg. Medit. p. 148. Endl. 3rd 

 Suppl. p. 55. Sphaerococceae, Lindl. Veg. Kingd. p. 25. 

 Part of Gasterocarpese, Sphaerococcoideae, and Chondrieae, 

 Dne. Class, p. 6465. 



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. Fructification 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, Tetraspores 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 



