4, Desmarestia : " Fructification unknown ; branches and leaves Woad, contracted at their origin, so as to appear sup pot on petioles; the edges garnished with small spines." —This includes F. aculeatus (Turn. t. 187.), which is very common on our shores, and F. ligulatus (t. 98.), which is rare. Lamoureux, as well as Stackhouse, is inclined to consider the marginal spinules as containing the seeds of the plants ; but 111r Turner has doubts on the subject.
5. Furcellaria : Fructification pod-shaped, subulated, simple or branched, smooth, stem and branches cylindrical, and without leaves."—This includes only F. lumbricalis (Turn. t. 6.) and its varieties.
6. Chorda : "Fructification unknown ; stern simple, cy lindrical, divided by internal dissephnents,"—the genicula intergerina of Roth. The name Chorda was first applied by Stack house to a small group of foci, consisting chiefly of F. filum and F. thrix. The latter is now known to be nothing but the Mum in a young state ; so that at present F. filum is to only species of this genus.
The second order, FLoitrnEze, are distinguished by their " organization being coralloidal ; their colour being purple or reddish, and acquiring lustre on exposure to the air." While fresh and living, the Floridere are of a purplish red colour, but have nothing of the lustre which they acquire when dead, and when they have been exposed for some time, in a moist state, to the action of light and air, so as that a degree of fermentation may be excited. It is in this order that the double mode of fructification (after wards described) is chiefly to be observed. The leaves of the Floridem are flat expansions, divided rather than branched, proceeding from a cylindrical stem, fixed by a disc More convex and less extensive than that of the Fuca eere. The leaf is just an expansion or continuation of the stem, and it is sometimes difficult to assign the re spective limits of these parts. All the flat portions are reckoned leaf, and all the round or compressed parts, branch or stein. Some of the leaves have nerves, of a deeper colour than the rest of the leaf: in these, the fruc tification is situated on the nerves, or at their extremities. In leaves destitute of nerves, the fructification is spread over the sot face of the leaf. The size of the Floridex is
not considerable, none of them much exceeding two feet in length. Lamoureux considers them all as annual or bien nial productions.
Ile makes two divisions : 1st, With flat leaves, Clan (lea, Delesseria, Chondrus : 2d, With cylindrical leaves, and wanting leaves, Gelidium, Laurencia, Hypnea, Acan thophora, Dumontia, Gigartina, Plocamium, and Champia.
1. Claudea. " Tubercles in a pod-shaped receptacle, which is attached to the nerve by its two extremities."— There is only one species, Claudea elcgans, which, accord ing to Lamouroux, is the most beautiful of all sea-weeds, for variety of colour, elegance of shape, and delicacy of or ganization. It is certainly the most curious of all the tribe. (See Plate CCLXI. Fig. I, 2, 3.) It was found on the coast of New Holland by the unfortunate Peron. The frond consists of a very fine membrane, which when dried is almost invisible to the naked eye, crossed by nerves forming a net-work. The fructification, as stated in the generic character, consists of rows of siliques, suspended by the two extremities between parallel nerves. Dried specimens exhibit fine teints of red, green, yellow, and vio let, passing into each other in the most pleasing manner. It is figured in ..'Jnnales du Museum, tom. 20, pl. 8. fig. 2. from whence our figure in Plate CCLXI. is copied. It is always desirable that a generic name should, if possible, suggest some idea of the kind of plant intended ; but al though this could easily have been accomplished in the present case, the unmeaning title of Claudea has been im posed ;—borrowed, we are told, from the Christian name of Lamouroux's father, Claude, and a better proof, surely, of filial attachment than of judicious nomenclature.
2. Delesseria. "Tubercles spherical, generally com pressed, somewhat like grape-stones (subgigartina), in nate, sessile, or pcdtmculated, situated on the nerves, the branches, the margin of the leaves, or scattered on their surface."—The colours are varied and brilliant. From rose-colour, or even bright scarlet, they descend to dark brown, passing through yellow, green, violet, and purple. Many of them are parasitical on the larger sea-weeds. The genus is subdivided into three sections.