124 STENOGRAMME. RHODYMENIA. 



1. S. interrupt^ Ag. ; frond stipitate, membranaceous, 

 flabelliform, more or less deeply laciniate ; laciniae repeatedly 

 dichotomous, their apices obtuse ; conceptacles forming a 

 nerve-like line through the centre of each lacinia, and usually 

 abruptly terminating opposite the fork. Harv. Phyc. Brit, 

 t. clvii. Delesseria interrupta, Ag. Spec. Alg. vol. 1, p. 

 179. 



Washed up from deep water. Annual. November. Very rare. Bovi- 

 sand, and near Plymouth, Dr. John Cocks (1846). Mount Edgecombe, 

 Rev. W. S. Hore. Minehead, Somerset, Miss Gifford. Root discoid. 

 Frond with a short stem, which soon becomes compressed, and rapidly ex- 

 pands into a fan-shaped membrane, 3 5 inches long, and about as wide. 

 This membranous lamina is either cleft to its base into numerous, linear, 

 dichotomous laciniae ; or the lower half of the lamina is undivided, the up- 

 per variously cloven. The margin is usually flat and very entire, but now 

 and then sends out minute leafy lobules ; and when the segments are 

 injured at the apex they frequently sprout out into proliferous growth. 

 Barren fronds are quite nerveless ; fertile ones have the centre of each la- 

 cinia traversed by a slender, raised, nerve-like line, which commences just 

 below one of the forkiugs and terminates nearly opposite to another fork : 

 this is the commencement of fructification. It rarely happens that the 

 whole line proves fertile; but portions varying from 1 to 4 lines in length 

 become much thickened, raised, and of a dark red colour, and at maturity 

 are filled with innumerable minute spores. Substance cartilagineo-mem- 

 branaceous. Colour a fine, clear, pinky-red, very similar to that of Rhod. 

 Palmetto,, which this plant resembles in several of its external characters. 

 For a fuller account see Phyc. Brit. I. c. 



II. RHODYMENIA. Grev. [Plate 16, A.] 



Frond flat, membranaceous, orsubcoriaceous, ribless, vein- 

 less, cellular ; central cells of small size, those of the surface 

 minute. Fructification : 1, convex tubercles (coccidid) hav- 

 ing a thick, cellular pericarp, and containing a mass of mi- 

 nute spores : 2, tetraspores, either zoned or tripartite, im- 

 bedded among the cells of the surface, scattered, or forming 

 cloudy patches. Name, p'oJeoj, red, and vpnv, a membrane. 



1. R. bifida, Good, and Woodw. ; frond thin and trans- 

 parent, rose-red, dichotomously divided from the base ; seg- 

 ments linear; the apices obtuse; tubercles generally con- 

 fined to the margin, sessile. Grev. Alg. Brit. p. 85 ; Hook. 

 Br. Fl. ii. p. 289 ; Wyatt, Alg. Danm. No. 66 ; Harv. Phyc. 

 Brit. t. xxxii. F. bifidus, E. Bot. t. 778. 0. ciliata; frond 

 somewhat thicker than usual, opaque, brownish-red, narrow, 

 much divided ; the margins fringed with leafy cilia. 



