P l a t e CXXXIV.
RHODYMENIA PALMETTA, Grev.
G e n . Ch a r . Frond flat, membranaceous or subcoriaceous, ribless, veinless,
cellular; central cells of small size; those of th e surface minute.
Fructification of two kinds on distinct individuals; 1, convex tuhercles
(coccidia) having a thick cellular pericarp, and containing a mass of
minute spores, on a central placenta. 2, tetraspores, either zoned or
tripa rtite, imbedded among th e cells of the surface, scattered, or formin
g cloudy patches. R h o d ym e n ia (Grev.),—from pobeos, red, and
vppv, a membrane.
R hodymenia F a lm e tta ; stem cylindrical, sub-simple, expanding into a
fan-shaped, rose-red frond, which is more or less deeply cleft in a
dichotomous manner ; segments linear-wedge-shaped, with broad,
rounded interstices, and a very entire, flat m a rg in ; apices, according
to the state of fructiflcation, either erose or ro u n d ed ; tubercles sessile,
very convex, marginal or sc a tte red ; tetraspores cruciate or tripartite,
forming deep-red sori in the expanded apices.
R hodymenia Palmetta, Grev. Alg. Brit. p. 88. 1 .12. Hook. Br. FI. vol. ii.
p. 290. Wyatt, Alg. Banm. no. 109. Harv. in Mack. M. Hib. p a rt 3.
p. 194. Harv. Man. p. 61. J . Ag. Alg. Medit. p. 153 ? Endl. Zrd Suppl.
p. 51. Mont. Alger, p. 68.
Sehsrococcus Palmetta, k ji. Sp. Alg. vol. i. p. 245. Ag. Syst. p. 215.
Lyngb. Hyd. Ban. p. 11. Spreng. Syst. Veg. vol.iv. p. 335. Kiitz. Phyc.
Gen. p. 410.
D e le sseria Palmetta, Lamour. Ess. p. 37.
H alymenia Palmetta, Gaill. Bict. Sc. Nat. vol. 53. p. 361.
Fucus Palmetta, Esper, Ic. Euc. p. 84. t. 40. {excl. syn.) Stack. Ner. Brit.
p. 102. 1 .16. Turn. Syn. vol. i. p. 21. Turn. Hist. Fuc. i. 13. E .B o t.
1 .1120.
Fucus bifidiis, Huds. El. Ang. p. 581.
S. Nicseensis, J . Ag. I. c. p. 1 5 3 .; frond simple, or once forked, very narrow,
rising from flbres.
H ab. On rocks near the verge of low water, and at a greater depth, b u t
more frequently on th e stems of Laminaria digitata. Annual.
Summer and autumn. Wot uncommon on th e British shores from
Orkney to Cornwall and Je rsey ; more abundant in th e south and
west. S ; at Sidmouth, Mrs. Griffiths and Miss Cutler.
Geogr. D is t r . Atlantic shores of Em-ope from Norway to Spain. Mediterranean
Sea. (The southern stations belong, probably, to B,. corallina.)
D e scr. Eoot a broad, common disc, sometimes accompanied by fibres. Eronds
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 gradiialy expands at
its summit into a fan-shaped, semicircular lamina, cuneate at base, and
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