CHONDRUS. 141 



globose, on the ramuli. Grev. Alg. Brit. p. 96 ; Hook. Br. 

 Fl. ii. p. 301 ; Wyatt, Alg. Danm. No. 28 ; Harv. Phyc. 

 Brit. t. cclxvi. Sph. Teedii, Grev. Crypt, t. 356. 



On rocks at extreme low water, very rare. Perennial. Elberry Cove 

 and Tor Abbey Bocks, Mrs. Griffiths. Fronds 2 5 inches high, from 

 half a line to a line in width; stem cylindrical, soon becoming compressed, 

 and finally flattened, either forked at the base or simple, set at intervals 

 of about a line with long, horizontal, distichous branches, attenuated at 

 each end, and pinnated with a second or third series of patent subulate 

 ramuli ; the whole forming a broadly ovate or fan-shaped frond. The ra- 

 muli are frequently very much lengthened out and filiform. Tubercles 

 have not yet been found in this country ; they occur on the ramuli. Co- 

 lour purplish, becoming brighter in fresh water, and finally yellowish. 

 Substance flaccid, but becoming horny when dry, and not adhering to 

 paper. 



4. G. mamillosuSj Good, and Woodw. ; frond thick, flabel- 

 liform, channelled, irregularly dichotomous; segments ob- 

 long-wedge-shaped ; tubercles roundish or ovate, supported 

 on little stalks, scattered over the disk of the frond. Grev. 

 Alg. Brit. p. 127 ; Hook. Br. Fl. ii. p. 302 ; Wyatt, Alg. 

 Danm. No. 117; Harv. Phyc. Brit. t. cxcix. ; E. Bot. t. 

 1054. 



On rocks and stones near low-water mark, common. Perennial. Au- 

 tumn and winter. Fronds 3 6 inches high, cylindrical at base, but gra- 

 dually widening into a compressed, and finally flat, wedge-shaped frond, 

 which is either once or twice forked or repeatedly dichotomous ; the seg- 

 ments all wedge-shaped, from a line to half an inch in breadth ; the apices 

 acute. Tubercles roundish, borne on short, filiform processes, produced in 

 great plenty by the surface of the upper segments, and which, in cases of 

 imperfect fructification become leaflets. Colour a dark purple. Substance 

 tough. 



IV. CHONDRDS. [Plate 17, D.] 



Frond cartilaginous, nerveless, compressed or flat, flabel- 

 liform, dichotomously cleft, formed internally of three strata ; 

 the inner of densely packed longitudinal fibres ; the medial 

 of small, roundish cells ; the outer of vertical, coloured mo- 

 niliform filaments. Fructification : 1, prominent tubercles 

 (nemathecia) composed of radiating filaments, whose lower 

 articulations are at length formed into spores (?) ; 2, tetras- 

 pores collected into sori, immersed in the substance of the 

 frond ; 3, favellidia, immersed in the frond, and scattered 

 over its segments, containing minute spores. Name, from 

 x;ovfy>of, cartilage. 



1. C. crispus, L. ; frond, thickish, cartilaginous, dichoto- 



