Ser. RHODOSPERME. Fam. Nemastomec. 
Piate XCVILI. 
IRIDHA EDULIS, Bory. 
Gen. Cuar. Frond flat, carnoso-cartilaginous, dull ted; the central sub- 
stance composed of densely interwoven, longitudinal fibres; the peri- 
phery of closely packed, horizontal, moniliform filaments. Fructifica- 
tion of two kinds, on distinct individuals; 1, spherical masses of 
spores (favellidia) immersed in the frond; 2, ¢e¢raspores forming a 
stratum at the base of the filaments of the periphery. Irma (Bory), 
—from iris, the rainbow; because some species reflect rainbow 
colours when growing under water. 
Tria edulis; frond undivided, obovate, rounded at the apex, wedge- 
shaped at the base; with a short stem. 
Irip#a edulis, Bory, in Dict. Class. d Hist. Nat. vol.ix.p.15. Grev. Alg. 
Brit. p. 158. t.17. Hook. Brit. Fl. vol. ii. p.308. Wyatt, Alg. Danm. 
no. 78. Harv. in Mack. Fl. Hid. part. 3. p. 189. Harv. Man. p. 53. 
Endi. 3rd Suppl. p.37. Kiitz. Phyc. Gen. p. 396. 
HatyMEnI< edulis, 4g. Sp. Alg. vol.i. p. 202. 4g. Syst. p. 242. Hook. 
Fi. Scot. part 2. p.107. Spreng. Syst. Veg. vol. iv. p. 333. 
DELEsSERIA edulis, Lamour. Ess. p. 38. 
Utva edulis, Decand. Fl. Fr. vol.ii. p.12. Grev. Fl. Edin. p. 298. 
Fucus edulis, Stack. Ner. Brit. p.57.t.12. With. vol.iv.p.101. Turn. Syn. 
vol. i. p.180. Turn. Hist. t.114. £#.Bot.t.1307. Hook. in Fl. Lond. 
cum icone. 
Fucus dulcis, Gm. Hist. Fue. p. 189. t. 26 (the figure only ; the description 
belongs to F. palmata). 
Fucus lactuca, Esper, Ic. Fuc. vol. i. p. 129. t. 64. 
Fucus carnosus, Schmidel, It. p.76. Esp. 7.c. p. 150. t. 76. 
Fucws palmatus, 8. Lightf. Fl. Scot. p. 935. 
Has. On marine rocks, near low-water mark. Perennial. Fruiting in 
winter. Frequent on the shores of the British Islands, from Orkney 
to Jersey. 
Grocer. Distr. Atlantic shores of Europe, from the shores of Iceland (Esper) to 
Spain (49.). Baltic Sea, Agardh, Aresch! Mediterranean at Malaga, 4g. 
Cape of Good Hope, according to a specimen in Herb. Paris, 4g. 
Descr. Root, an expanded callus. Fronds numerous from the same base, from 
six inches to afoot or more in length, and from two to six inches in 
breadth at the widest part, rising with a short, cylindrical stem, of a few 
lines in length, which becomes first compressed, then quite flat, and gra- 
dually expands into the cuneate base of a perfectly simple, obovate frond, 
which is very obtuse and rounded at the apex. It is subject to very little 
natural variation in form, except in being occasionally oblique, one side ex- 
panding more rapidly than the other; but no plant is more subject to 
injury either from the attacks of marine animals, or laceration by the 
