A few of the smaller and more delicate kinds seem capable of,affording colouring matter or paint. Ginanni describes one under the name of Fuco tintorio. This Mr Turner considers as probably F. purpureus, which is very common in the Mediterranean, and gives out a beautiful chocolate dye in fresh water.
It may be mentioned, that in the North of Scotland, a kind of sauce for fish or fowl, somewhat resembling ketchup, is made from sea-weeds; frequently from tile cup-like frond or base of F. loreus.
The mucus from the vesicles of F. vesiculosus, and similar species, has been recommended in diseases of the glands, by Dr Russell; and F. helminthocortos, (Turn. t. 233 ) a small Mediterranean species, though little known in Bri tain, has long been employed by medical men on the con tinent as a vcrmifuge, under the name of Moss or Coralline of Corsica.
Some of the small red species are very ornamental when displayed and are used not only to embellish the cabinet of the naturalist, but apartments in general. The foreign species chiefly employed for this purpose, is F. cartilaginous, which abounds at the Cape, and is remark able for the regularity and elegance of its form, and the richness of its tints.
The native species most generally used for forming mi mic trees or landscapes, is F. coccineus. The frond is com pressed, in substance between membranaceous and carti laginous, much and irregularly branched ; the ramuli subu late, disposed in alternate parcels of three or four each. As formerly observed, two kinds of fructification are to be found on different individuals of this species ; both spherical sessile capsules, and lanceolate siliqum. It is beautifully figured by Turner, (Hist. Fuc. t. 59) and also by Stack house, in a frontispiece to one of the fasciculi of his Ne•cis Britannica, (p.106.) It is singular that this species, though very common, escaped the notice of Linnaeus. When it is dexterously expanded on very smooth white paper, or on the glossy interior of large flat shells, the effect is very beautiful. It is generally of a bright red colour, but some times tinged white or yellow. It grows about three or four inches long. In minuteness of ramification, it is ex celled only by F. asparagoide8,(Turn. t.101.) a species of much less frequent occurrence.
F. p/umosus is likewise very ornamental. The frond is compressed, cartilaginous, much and irregularly branched; the branches are repeatedly pinnated, producing the fea ther-like appearance, from which the name has been given. It is of a purple colour, often inclining to yellowish brown. It is generally from three to live inches long; lint in the north of Scotland it reaches six or seven inches. Still farther to the north of Europe, as on the northern coast of Norway, it grows to yet a larger size; so that it may truly be reckoned a northern plant. It is generally found attach ed to old stems of fucus digitatus.
F. alatus is the most abundant of all the small ornamental sea-weeds, being very common on stalks of F. digitatus. The frond is membranaceous, very tender, mid-ribbed, linear, the segments alternately pinnated. It is
three or four inches high, and of a fine purplish red colour.
Preserving of Sea-weeds, Many of the fuel, and particularly the Floridx of La rnouroux, make a beautiful appearance when preserved in a herbarium or hortus siccus. All of them require to be soaked for some time in fresh water, and they are the better for being repeateilly rinsed in renewed basins of water, to cleanse away and extract as much as possible the sea-salt which adheres to them, or with which they are impregnated. The larger sort need no other preparation ; but are to be dried between folds of blotting paper, and pressed in the manner of herbaceous plants. The finer leaved fuci must be treated in a different way. After being washed, as above directed, in repeated waters, till no impurities of any kind remain, they are to be separately floated out in a large shallow dish containing water, so that their most minute and deli cate branches may be fully expanded. For disentangling the nice ramifications, a common pin, or a sharp-pointed pen, may be employed. A piece of stiff, but fine and smooth writing paper, is then to be gently introduced under the specimen, and the minute branchlets being again spread out where they may have been disordered, the paper is to be cautiously and slowly inclined, and at last drawn out, so as to contain on its surface the plant in its fully expanded state. After this, most of the delicate species, it carefully dried and pressed, adhere to the paper by their own gluten, and require no farther care. Mr Turner mentions that he fixes the non-adhesive kinds by means of a cement made from F. ciliatus and crispus of our shores. These are boiled in water over a quick fire, and soon become melted : on cooling, they form a gluten, not to be relied on as a strong cement, but which is well adapted for a herbarium, as it neither imparts a stain like glue, nor a glare like gum. If the paper be slightly rubbed over with the mucilage, and a delicate membranaceous plant afterwards placed on it, it will become sufficiently fixed merely by moderate pressure. Some collectors, finding that any kind of paper is apt to curl up, expand the delicate species over a plate of glass, and, after allowing the water to drip off, transfer the specimen carefully to the paper.
To inland collectors, who occasionally make an excur sion to the shore, it may be useful to know, that all the preparation that is necessary at the sea side is to dry the specimens moderately in the free air, and tie them loosely up in strong brown paper. In this way they may be carried to a great distance, and kept for some days. On being immersed in fresh water, they in general expand as fully as before; but it must be confessed that the colour of some kinds is extremely apt to change. In the vasculuni, or botanic box, which serves so well for preserving herba ceous land plants, specimens of marine plants very rapidly undergo the putrefactive fermentation. (a. x.)