Ser. GONGYLOSPERMEiE. (9) Fam. RHODYMENIACEJl. 



Plate LXIX. 

 RHODYMENIA PALMETTA.— G^/m 



Gen. Char. — Fronds flat, subcoriaceous, cellular, without veins or midrib. Fructification 

 of two kinds, on distinct plants : 1. Convex tubercles (coccidia), containiug a 

 mass of minute spores attached by a central placenta ; 2. Tetraspores, cruciate, 

 imbedded in cloud-like patches among the surface cells of the frond. Name from 

 ^o5eoy, "red," and u^uV, "a leaf or membrane." 



Rhodymenia Palmetta. — Frond with a short cyhndrical stem, flat, 

 four to six times dichotomously divided in fan-shaped manner ; segments 

 with romided axils, obcuneate, npper divisions Hnear oblong, with 

 rounded apices ; tubercles almost spherical, sessile ; tetraspores imbedded 

 in the apices of the segment, forming dark red sori. 



Rhodymenia Palmetta.— Grev. Alg. Brit. p. 88, t. 12 ; Hooh. Br. Fl. vol. ii. p. 290 ; 

 Wyatt, Alg. Damn. No. 109 ; /. Ag. Alg. Medit. p. 153 ; Endl. 3rd 

 Suppl. p. 51 ; Mont. Alger, p. 68; Harv. in Mack. Fl. Hib. part 3, 

 p. 194 ; Harv. P. B. plate 134 ; Harv. Man. p. 125 ; Harv. Syn. 

 p. 104 ; Atlas, plate 39, fig. 180; Harv. N. B. A. part 2, p. 149 ; 

 /. G. Agardh, Sp. Gen. Alg. vol. ii. p. 378. 



SPH.EROCOCCUS Palmetta. — Ag. Sp. Alg. vol. i. p. 245 ; Ag. Syst. p. 215 ; Lyngh. 



Hyd. Dan. p. 11 ; Spreng. Syst. Veg. vol. iv. p. 335 ; Kutz. Phyc. 



Gen. p. 410. 



Delesseria Palmetta. — Lamour. Ess. p. 37. 



Halymenia Palmetta. — Gaill. Diet. So. Nat. vol. liii. p. 361. 



Fucus Palmetta.— Espier, Ic. Fuc. p. 84, t. 40 (excl. syn.) ; Stach. Ner. Brit. 

 p. 102, t. 16 ; Turn. Syn. vol. i. p. 21 ; Turn. Hist. Fuc. t. 73 ; E. 

 Bot. t. 1120, 



Fucus hifidus. — Huds. Fl. Angl. p. 581. 



/3 Mcceensts. — Frond simple, sometimes once forked, very narrow, rising 



from fibres. 



/. Ag. 1. c. p. 153 ; Harv. P. B. plate 134, fig. 3 ; /. G. Agardh, Sp. Gen. Alg. 

 vol. ii. p. 379. 



Hab. — On rocks, shells, and stems oi Laminaria digitata at low- water and a greater 

 depth. Annual. Summer and autumn. Common on the British shores, but most so on 

 the west coast. /3 at Sidmouth {Mrs. Griffiths, Miss Cutler). 



Geogr. Dist. — Atlantic shores of Europe ; Mediterranean Sea. 



Description. — Root, a broad flattened disc. Fronds densely tufted, 

 two to five inches in length, with a short cylindrical stem a quarter of 



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