196 ALG/E RHODOSPERME^E-. [Rhodomela. 



(alternately secund and pectinate.) Fructification of two 

 kinds : sphserical sessile capsules, and lateral minute pro- 

 cesses, containing oblong granules, transversely divided into 

 several parts by pellucid lines. Grev. Name ; irXoicafio?, in- 

 tertwined hair ; from the finely branched fronds. The exotic 

 genus Thamnophora, Ag. f. Grev., closely accords with the 

 present in habit, and merely differs in the structure of the 

 granules of the secondary fructification ; a character, in my 

 opinion, by no means sufficient to separate plants otherwise 

 so nearly related. 



1. P. coccineum, Lyngb. Scarlet Plocamium. Grev. A/g. 

 t. 12. Hook. Br. Fl. v. ii. p. 293. — Fucus coccineus. Turn. 

 Hist. t. 59. E. Bot. t. 1242. 



Sea-shore?, ven^ common. Fronds 5 — 6 inches long, much branched, 

 bright rose-colour ; ramuli regularly alternately secund and pectinate. 



4<X Odonthalia. Lyngb. Odonthalia. 



Frond plane, between membranaceous and cartilaginous, dark 

 vinous-red, with an imperfect or obsolete midrib, alternately 

 toothed at the margin. Fruct. marginal or axillar}', or in 

 the teeth; 1. Capsules, containing pear-shaped seeds, fixed 

 by their base ; 2. slender processes (stichidia), containing 

 ternate granules. Grev. — Name ; oBovs, o£oi>tos, a tooth, and 

 Oakaam], the sea; a marine plant, with a toothed margin. 



1. O. dentata, Lyngb. Toothed Odonthalia. Frond vaguely 

 branched in an irregularly pinnate manner ; branches linear- 

 oblong, narrowed at base, alternately pinnatifid ; laciniae sharply 

 toothed at the truncate extremities ; capsules clustered on 

 branched peduncles. Hook. Br. Fl. v. ii. p. 293. — Fucus den- 

 tatus. E. Bot. t. 1241. 



Confined to our northern shores, where it is very common. Fronds 

 4 — 6 inches high, very dark. 



41. Rhodomela. Jig. Rhodomela. 



Frond cylindrical or compressed, filiform, much branched, 

 coriaceo-cartilaginous (the apex sometimes involute.) Fruct. ; 

 subglobose capsules, containing free pear-shaped seeds, and 

 pod-like receptacles, with imbedded ternate granules. Grev. 

 Name ; po?os, red, and /jeXas, black ; in allusion to the change 

 the species undergo in drying, from red to blackish. 



1. R. Lycopodioides, Ag. Club-moss Rhodomela. Frond 

 elongate, mostly simple, beset with short, closely imbricated, 

 slender, hiir-like ramuli, which are generally forked near the 

 apices. Hook. Br. FL v. ii. p. 294 — Fucus Lycopodioides. Turn, 

 Hist. t. 10. E. Bot. t. 1163. 



