A local disposition may he traced in some cases. In the East Indies, for example, the Straits of Sunda have afford ed two curious species, with leaves resembling holly and dwarf-oak, F. aquifolius and ilicifolius of Turner (t. 50, 51.) The uncommon looking F. muricatus of the same author, (t. 112.) is a native of the same Straits. None of these have hitherto been found elsewhere. F. tenax, (Turn. t. 125.) one of the most useful of the tribe, is peculiar to the seas of China. The Caulerpx may be considered as be longing to the Red Sea and New Holland. At the Cape of Good Hope, the place of our digitatus and bulbosus is occupied by F. buccinalis, (Turn. t 139.) which is often observed floating about in great quantity, and from its fis tular and inflated stem, has received from navigators the name of trumpet-weed: by them its appearance is hailed as a sure prognostic of the vicinity of the Cape. F. flaccidus of Turner (t. 61.) is there parasitical on the larger foci, like alatus and coccineus with us. Two Cape species are remarkable for being elegantly fringed along the margin, F. crinaceus (Turn. t. 26.) and F. vittatus, or ribbon weed, (t. 64.) Some are peculiar to the nnrth-west coasts of Am' i ica. Among these may be mentioned F. IVIenziesii, (Turn. t. 27.) named in honour of Mr Menzies, who at tended Captain Vancouver in his voyage of discovery, but whose valuable researches in the department of natural history are brought to light only in a tardy and almost ac cidental manner, he having received no encouragement from Government to publish his many botanical disco vcrics. To it may be added F. herbaceus, of Turner, (t 99,) resembling a broad-fronded ligulatus; two others of Turner, F. osmundaceus (t. 105.), cordatus (t. 116.), and F. floccosus of Esper (hones, t. 100.) ; with F. costatus of Turner, (t. 226.) curiously ribbed. Others of the north west American species are found also in other countries: F. bracteatus (Hist. Fuc. t. 25.) occurs at the Cape, and F. ovalis t. 81.) is common to Nootka Sound and the shores of Britain. A few may be set down as peculiar to the Mediterranean, as F. nervosus, of Decandolle (Turn. t. 43.), and linifolius of Turner, (t. 168.) F. purpurens, Fuc. t. 224.) is very plentiful in the Mediterranean ; but it is likewise found in the Red Sea. F. viridis, which is met with on the southern shores of England, but so sparingly as to be accounted a botanical discovery, occurs abundantly as a parasite on F. vesiculosus and serratus on the coast of France. These, as is well known, are two of our most common kelp fuci on the shores of Scotland; but in this country F. viridis never appears upon them. The very elegant small species F. asparagoides and Wigghii (Hiet. Fuc. t. 101, 102.) have not, it is believed, been found be yond the precincts of the British islands, and have more frequently occurred on the beach at Yarmouth than else where. F. pusillus seems also to he local, and is described as creeping like a jungermannia, on the red sandstone rocks at Sidmouth in Devonshire. (.her. Brit. t. 6.) A few may be ranked as arctic species ; particularly F. distichus of Linnaeus, (Turn. t. 4.) and ramentaccus, (t. 149.) F. lyco podioides grows plentifully on the most remote shores of Norway, and occurs sparingly on the coast of Scotland. F. soboliferus (nor. Dan. t. 1066.) is common in Finmark, and has been detected on the shores of the Orkney Islands by Mr Fothergill. F. plumosus is one of the ornaments of the shores of the south of England ; but it increases in size and beauty as we proceed northwards, and is much finer in Orkney than in Cornwall : it has been observed even in Davis Straits.
Many species, which grow most abundantly on all the shores of Europe which are exposed to the great ocean, are not to be found in the Baltic Sea, the waters of which arc less salt, and are little affected by the influence of the tides. Hasselquist, in his Travels, expresses delight at
meeting with our common F. saccharinus when he first cleared the Baltic. Some of those species, particularly F. vesiculosus, which grow very far up in the lochs or friths of the west of Scotland, do not appear in the Baltic. F. nodosus and serratus, it may be added, continue near to the heads of the Scottish arms of the sea ; and F. canaliculatus is found in the most extreme corners to which the sea beach can be said to extend ; being exceeded only by F. amphibius, (Turn. t. 109,) which grows like a coralloidal lichen, parasitically on herbaceous plants, in salt marshes. On the banks of rivers too, where they enter the sea, F. caniculatus is found very high up, even among the brack ish water.
On our open sea-shores a certain order is observed in the habitat of the fuci, each species occupying pretty re gularly its own zone or station. F. filum or sea-laces grows in water some fathoms deep. In places where the tide seldom entirely ebbs, but generally leaves from two to three feet of water, grow F. esculentus and bulbosus, and the larger specimens of digitatus and saccharinus, with some small kinds, as F. palmatus, siliquosus, and sangui neus. In places uncovered only at the lowest ebbs, small er plants of digitatus and saccharinus abound, with F. lo•eus or sea-thongs. On the beaches uncovered by every tide, F. serratus occurs lowest down, along with crispus and mamillosus ; next comes F. nodosus ; and higher up, F. vesiculosus. Beyond this F. canaliculatus (already men tioned) still grows, thriving very well if only wet at flood tide, and though liable to become dry and shrivelled during a great part of the day. Lastly, F. pygmaeus, figured by Lightfoot, (t. 32.) is satisfied if it be within reach of the spray.
Floating Sea-weeds.
The great accumulations of sea-weed found floating in the Atlantic, Pacific, and Indian Oceans, on each side of the equator, nearly to the 40th degree of north and south latitude, have already been alluded to; but they are not undeserving of further attention.
The Mar do Sargasso (or sea of sea-weeds) of the Por tuguese, stretches between the 18th and 32d parallels of north latitude, and the 25th and 40th meridians of west longitude. It is often called the Grassy Sea, and is men tioned by many navigators. It is thus described by Bar row, in his Voyage to Cochinchina : " The surface of the sea for several days was literally covered with plants. Some of them were many feet in diameter ; others only a few inches : all appeared in a growing state. The globose berries (by which Mr Barrow means the air-vesicles) were in some plants green ; in others red. If taken out of the water, the plant became flaccid, and in the space of four and twenty hours turned brown or black. The naturalist in every plant may find a great variety of marine insects and worms, some naked and others with testaceous coverings. Those plants with green vesicles, it may be remarked, were probably specifically distinct from such as had red.
It is stated by Humboldt in his Personal Narrative, that in the great basin of the Atlantic Northern Ocean, there exist two banks of floating sea-weed. The most extensive is a little west of the meridian of Fayal, one of the Azores, between latitude 25° and 36°. Violent north winds some times prevail in this space, and drive the sea-weed to the low latitudes, as far as 24° or even 20°. Vessels returning to Europe, either from Monte Video or the Cape of Good hope, cross the bank nearly at an equal distance from the Antilles and Canaries. The other occupies a much small er space between 22° and 26°, eighty leagues west of the meridian of the Bahama Islands. It is generally traversed by vessels on the passage from the Caiques to the Ber mudas.