Near Tierra del Fuego immense growths have been seen, with stems between three and four hundred feet in length. Great sub-ocean forests of kelp are there, and floating fucus-islands, with leaves or fronds seven or eight feet from base to tip, covered with living animals, and having air-vessels several inches long. In the matter of colour no great variety exists. Sea-weeds are generally either grass-green, olive-brown, or red. The green are usually close to land, and they never grow beyond touch with direct sunlight. The olive-brown are the more abundant; and the red belong, perhaps, more often to deep water. A large majority grow attached either to stones or to the shallow sea-bottom, but some kinds float unattached. To this last class belong the masses of weed in the Sargasso Sea--the centre of the North Atlantic currents. Round that huge collection of weeds and drift, which reaches over something like two hundred and sixty thousand square miles, the entire North Atlantic slowly revolves. And of these weeds--called “Sargassum”--none are attached to rock or ground, but all float loosely in mid-ocean. They seem to flourish thus, though the fact that fructification is not found upon them points to a somewhat unusual condition of things. Sea-weeds more often multiply by means of spores, which is a form of vegetable-growth inferior to that of seeds. All spore-growing plants, whether on land or in the sea, take a lower rank than seed-growing plants. A still lower and humbler method has been earlier described--that of simply dividing into half. There is yet another way by which ocean-weeds increase, and it reminds one curiously of the gardener’s plan of growth by cuttings. In rough weather, on shallow reaches not far from land, the waves tear quantities of sea-weed fronds from their moorings, and carry them to shore or to rocky parts, where they become entangled, and are held fast. There, if later waves do not again dislodge them, and if other circumstances are favourable, the wandering fronds settle down, attach themselves, and become fresh plants. So in this case the waves act as gardeners, and make cuttings of ocean-plants. While plant-life in the ocean is plentiful in amount and abundant in variety, it is confined within limits. By far the greater part of Sea-weed existence is contained in the Hundred-fathom limit--that is, within six hundred feet of the surface. Not many kinds, indeed, can grow in anything like as much depth as five or six hundred feet. Sea-weeds in abundance are found on shallow shores, near continents and islands; on the zone between high and low tides; and on gently-shelving slopes beyond that zone. Floating unattached sea-weeds, of the type which belongs to the Sargasso Sea, may be anywhere, over the deepest depths of the ocean. These, however, are not found living and growing very far beneath the surface: and Ocean’s depths are without any kind of vegetable-life, except probably bacteria. CHAPTER XVI.