121 SYNOrSIS OF BRITISH SEAWEEDS. 



•// in Diet, class. dllist. X<i/. r. \). p. 15. 

 (ATLAS, PI. \LVII. Pig, 215.) 

 Halymenia edulis, Ag. Delesseria edulis, Lamour. Olva edulis, 

 DC. Fucus edulis, Stack. P. dulcis, Ghn. P. lactuca, J&p. 

 rnosus, Schmidel. F. palmatus, var., Lightf. 

 Hab. On marine rocks, near low-water mark. Perennial. Fruit- 

 ing in winter. 

 It is a singular, and almost an unaccountable fact, thai 

 this plant, than which none are more invariable in cha- 

 racter, or more distinct in general appearance, should have 

 [founded with Rhodymenia palmetto., a plant 

 of a very different form, different structure, and different 

 substance. Withering was the first author who clearly 

 defined the present; but it is to be regretted that lie as- 

 signed the specific name edulis to it, for, though a favourite 

 certainly with marine worms, it rarely constitutes a part 

 of human food ; the It. palmata being the true eatable 

 Fucus or Dulse of the Scotch and Irish. 



LXXIII. CATEXELLA. 



211. Opuntia {The Indian-Fig Catenella) ; fronds rising from a 

 mass of creeping fibres, vaguely branched ; pseudo-articu- 

 lations lanceolate or elliptical, about four times as long as 

 broad, Grev. Alg. Brit. p. 166. t. 17. (Atlas, PL XLIV. 

 Fig. 201.) 

 Chordaria Opuntia, Spreng. Lomentaria Opuntia, Gaill . Haly- 

 menia ? Opuntia, Ag. Chondria Opuntia, JIooJc. Gigartina 

 Opuntia, lamour. G. pilosa, Lamour. Rivularia Opuntia, 

 Gm. Fucus Opuntia, Good and Woodic. F. repens, ightf. 

 F. csespitosus, Stack. Ulva articulata, var., Huds. 

 Sab. On submarine rocks, piles, etc., near high-water mark. 

 Perennial. Rarely found in fruit. 

 This curious little plant, named from the resemblance of 

 its branches to the jointed leaves of the Cactus Opuntic, 

 can only be confounded with a dwarf state of Chylocadia 

 articulata, which is about the same size. But, not to speak 

 of difference of structure, the brighter colour, cylindrical 

 joints, delicate substance, acute angles, and forked fronds 

 of the latter, sufficiently distinguish it. 



LXXIY. CRUORIA. 



215. pellita {The skin-like Cruoria); frond gclatinoso-coriaceon?, 

 forming a skin on the surface of rocks, composed of vertical. 



