Ser. GONGYLOSPERMEJE. ( 25 ) Fam. RHODYMENIACE^. 



CATENELLA OVV^TIA.—Grev. 



Gen. Char. — Frond filiform, constricted, solid, the central portion composed of a very 

 lax network of delicate, anastomosing, jointed filaments, from which arise vertical 

 jointed, dichotomous filaments, forming the outer stratum, very dense at the 

 surfoce. Fructification of two kinds, on distinct plants : 1. Capsules, formed by 

 the metamorphosis of the ramuli, and containing a mass of minute angular spores ; 

 2. Tetraspores, zonate, immersed among the dichotomous filaments and formed by 

 their metamorphosis. Name from ca^meZ/a, diminutive of ca<e« a, "a chain." 



Catenella opuntia. — Fronds arising from creeping filaments, densely 

 tvifted, constricted ; branches few, irregular. 



Catenella opuntia. — Grev. Ahj. Brit. p. 166, t. 17 ; Hook. Br. Fl. vol. ii. 

 p. 309; Wyatt, Alg. Danm. No. 126; /. Afj. Alg. Medit. \}. 89; 

 Endl. 3rd Suppl. p. 37 ; Kiitz. Pliyc. Gen. p. 394, t. 76, f. 4 ; Harv. 

 in Mack. FJ. Bib. part 3, p. 188 ; ffarv. P. B. plate 88 ; Harv. Man. 

 p. 151 ; Harv. Syn. p. 124 ; Atlas, plate 44, fig. 204. 



Chokdaria opuntia. — Spvreng. Syst. Yerj. vol. iv. p. 330. 



LoMENTARiA opuntia. — Gain. Diet. Hist. Nat. vol. liii. p. 367. 



Halymenia ? opuntia. — Ay. Sp. Alg. vol. i. p. 217 ; Syst. p. 245. 



Chondria opuntia. — Hook. Fl. Scot, part 2, p. 106 ; Grev. Fl. Edin. p. 292. 



Gigartina opuntia. — Lamour. Ess. p. 49. 



GiGARTiNA pilosa. — Lamour. 1. c. p. 49 (sec. Ag.). 



EivuLARiA opuntia. — Gm. Eng. Bot. t. 1868. 



Fucus opuntia. — Good. & Woodw. in Linn. Trans, vol. iii. p. 219 ; Stack. Ner. 

 Brit. p. 104, t. 16 ; Turn. Syn. Fuc. vol. ii. p. 387 ; Turn. Hist. 

 t. 107. 



Fucus repens. — Lightf. Fl. Scot. vol. ii. p. 961 ; With. vol. iv. p. 91. 



Fucus ccespitosus. — Stack. Ner. Brit. p. 59, t. 12. 



Ulva articulata, j3. — Huds. Fl. Angl. p. 569. 



Hab. — On rocks, &c., near high-water mark. Perennial. Common, but rare in 

 fruit. 



Geogr. Dist. — Atlantic shores of France and Spain ; Mediterranean Sea ; New 

 Zealand (Dr. Hooker). 



Description. — Roots composed of creeping, branched filaments. 

 Fronds, arising from these, filiform, constricted at intervals of from half 

 a line to a line, from half an inch to an inch in height, densely tnfted, 

 formmg continuous patches, often spreading over a considerable surface, 

 sparingly branched ; branches arising immediately under the constriction, 

 mostly opposite, or solitaiy, sometimes again once or twice divided in 



VOL. II. E 



