Ser. RnoposPERME®. Fam. Spherococcoidec. 
Puate CXXXIV. 
RHODYMENIA PALMETTA, Grev. 
Gen. Cuar. Frond flat, membranaceous or subcoriaceous, ribless, veinless, 
cellular; central cells of small size; those of the surface minute. 
Fructification of two kinds on distinct individuals ; 1, convex tubercles 
(coceidia) having a thick cellular pericarp, and containing a mass of 
minute spores, on a central placenta. 2, ¢e¢raspores, either zoned or 
tripartite, imbedded among the cells of the surface, scattered, or form- 
ing cloudy patches. RuopymeNta (Grev.),—from pédeos, red, and 
tunr, a membrane. 
Ruopymenia Pa/metta ; stem cylindrical, sub-simple, expanding into a 
fan-shaped, rose-red frond, which is more or less deeply cleft mm a 
dichotomous manner; segments linear-wedge-shaped, with broad, 
rounded interstices, and a very entire, flat margin; apices, according 
to the state of fructification, either erose or rounded ; tubercles sessile, 
very convex, marginal or scattered; tetraspores cruciate or tripartite, 
forming deep-red sori in the expanded apices. 
RwAopYMENIA Palmetta, Grev. Alg. Brit. p. 88. t.12. Hook. Br. Fl, vol. ii. 
p- 290. Wyatt, Alg. Danm. no.109. Harv. im Mack. Fl. Hib. part 3. 
p- 194. Harv. Man. p.61. J. Ag. Alg. Medit. p.153? Endl. 3rd Suppl. 
p- 51. Mont. Alger. p. 68. 
Spu#rRococcts Palmetta, 4y. Sp. Alg. vol.i. p. 245. Ag. Syst. p. 215. 
Lyngb. Hyd. Dan. p.\1. Spreng. Syst. Veg: vol.iv. p.335. Kaitz. Phye. 
Gen. p. 410. 
DerveEsserta Palmetta, Lamour. Ess. p. 37. 
Ha tyMENIA Palmetta, Gall. Dict. Sc. Nat. vol. 53. p. 361. 
Fucus Palmetta, Esper, Ic. Fuc. p. 84. t.40. (excl. syn.) Stack. Ner. Brit. 
p- 102. t.16. Zurn. Syn. vol.i. p. 21. Turn. Hist. Fuc.t. 73. E. Bot. 
t. 1120. 
Fucus bifidus, Huds. Fl, Ang. p. 581. 
8. Niceensis, J. Ay. /.c. p. 153.; frond simple, or once forked, very narrow, 
rising from fibres. 
Has. On rocks near the verge of low water, and at a greater depth, but 
more frequently on the stems of Laminaria digitata. Annual. 
Summer and autumn. Not uncommon on the British shores from 
Orkney to Cornwall and Jersey; more abundant in the south and 
west. 8., at Sidmouth, Mrs. Griffiths and Miss Cutler. 
Grocer. Distr. Atlantic shores of Europe from Norway to Spain. Mediterra- 
nean Sea. (The southern stations belong, probably, to R. corallina.) 
Descr. Root a broad, common disc, sometimes accompanied by fibres. Fronds 
densely tufted, rising with a more or less evident, simple or rarely divided 
stem, cylindrical and filiform below, compressed above, and from a quarter 
of an inch to one or two inches in length: this stem gradually expands at 
its summit into a fan-shaped, semicircular lamina, cuneate at base, and 
