THE FARMER'S MAGAZINE. 



105 



otherwise the same part throws out many fibres, or iu the 

 larger kinds cord-like processes, by means of which it grapples 

 so firmly to the stone as to be almost insepar.ihle without 

 laceration. In either case these processes are rather to be re- 

 garded as prefigurations of root, developed only to secure the 

 plant a fixed habitation, than as fulfilling the more active 

 functions belonging to that important organ in the higher 

 classes of vegetation : the nutrition of the algse being appa- 

 rently derived by absorption from the aurrounding medium, 

 taking place over their whole surface. 



The distribution of this vast series of aquatic organisms, of 

 which at least two thousand species are known to exist, is, like 

 that of aerial or terrestrial plants, much affected by climate 

 and other local circumstance?. Some cf them seem to be 

 limited to the colder or temperate parts of the globe, others 

 only exist in the warmer. Among those of marine develop- 

 ment, almost every sea and gulf, and every geographical de- 

 partment of the main ocean, possesses its characteristic vege- 

 tation. Like the plants of the land, too, they are apparently 

 influenced by soil, or rather, perhaps, by the nature of the 

 rock to which they adhere, cerlaiu species being never met 

 with but on media of peculiar composition ; thus limestone, 

 chalk, sandstone, basalt, &c., favour each the production of 

 some species in preference to that of others — a phenomenon 

 probably dependent rather ou their surface texture than 

 mineral character. Another circumstance deserving notice is 

 their individual tendency to solitary or associate growth. 

 Many kinds are but sparingly scattered or of rare occurrence, 

 while others delight to vegetate in masses. Some of the 

 smaller species cover large extents of surface, to the exclusion 

 of every other, .as the grasses do our meadows and pastures ; 

 while many of the larger are aggregated in mimic woods or 

 forests, each as striking in its characters, and as diversified in 

 its appearaiice, as those of the earth, in which the oak, the 

 beech, the hornbeam, and the fir respectively occupy the soil 

 and exposure to which they are naturally the best adapted. 



Considered in the aggregate, the vast mass of aquatic vejje- 

 tation is of small immediate importance to mankind. A few 

 of the marine species are employed ns food, especially iu times 

 of scarcity, by the poorer inhabitants of our own sea-coasts, as 

 well as by those of other countries; while three or four of the 

 number have even found their way to the tables of the luxuri- 

 ous, originally, perhaps, introduced with a view to medicinal 

 effect in scorbutic and scrofulous habits, though the discovery 

 of iodine, the principle upon which their action iu such cases 

 depends, has long since removed thera from the province of the 

 physician. Consisting chiefly of mucilage Knd albumen, they 

 are nutritious, and, in the absence of all deleterious proximate 

 principles, wholesome ; the latter character being due to the 

 simplicity of their cellular structure, which renders the lower 

 orders of plants generally incapable of elaborating the acid, 

 allcaloid, and other combinations that render so many cf the 

 complex forma of vegetation poisonous. The species best 

 known, and employed as food in Europe, are Ulua lacluca and 

 latissima, called green laver ; Porpliyru laciniata, purple laver; 

 BJiodomenia palmala, the dulse of Scotland ; and Chondrus 

 crisptts, the carrageen or Irish-moss of the druggist and her- 

 balists. RJiodomenia, especially, is much prized, and besides 

 being used as human food, is largely collected on some parts 

 of the shores of Nor way "and North Britain as fodder for cattle, 

 cows and sheep being so fond of it, that they are, not urifre- 

 qucntly, lost by straying out too far upon the rocks in search 

 of it when the tide is down. To these species may be added 

 Gracilaria lichenoides, Ceyloa-moss, much imported of late 

 years, and recommended as a substitute for animal jelly : it is 

 the vegetable substance of which the sea-swallow, Hirimdo 



e«CM?ert<a, of the Indian Archipelago, constructs its edible nests, 

 so much valued by Chinese epicures, as frequently to be sold 

 iu Pekin for their weight in gold. The use of the larger kinds 

 of seaweeds for burning in the manufacture of Icelp, and of 

 the promiscuous masses thrown on shore in stormy weather as 

 manure, will nearly complete the list of man's economical 

 adaptations of a vegetation, constituting one of the most im^ 

 pcrtant features of the world he inhabits. 



Limited as is the employment of the alga in human economy, 

 it dees not appear to contribute ou a scale proportioned to its 

 abuudant production to the maintenance of the animals be- 

 longing to its native element. Of the multitudes of molusca 

 and Crustacea that seek shelter, food, and recreation, in the 

 submarine u-eadows and groves, a comparatively inconsiderable 

 moiety derives subsistence from a dtill smaller number of spe- 

 cies ; and the great mass of oceanic vegetation .lives and mul- 

 tiplies its kind, and dies, without seemingly fulfilling the pur- 

 pose to which, on the first glance, we might suppose it des- 

 tined. To estimate the value of these obscure productions of 

 a medium so widely diffused as water, we must reflect that the 

 economy of Nature is based on a wider foundation than that of 

 man ; every item in her code has an influence, a bearing upon 

 every other ; and the more obvious reading of one of her laws 

 of action often proves on examination the less correct, if not 

 indeed altogether mistaken and untrue. 



The numbers and universal distribution of the plants before 

 us are evidence of their utility. The ocean, in every part 

 from the Polar seas to the Equator, swarms with them ; they 

 dwell iu every river and lake, in every stagnant pool and ditch; 

 even the ice and snow of Greenland and Nova Zembla have 

 their species, so have the fountains of the boiling Geysers. 

 Of their ministry we know not the extent. We know that 

 water exposed to the light of the sun for a day or two, depo- 

 sits a green cruat upon the interior of the vessel that contains 

 it ; and that if from any cause this deposit does not take 

 place, the water becomes putrid, within a longer or shorter 

 period, depending upon the temperature under which it is 

 kept. We see in every little pool left by the rain a similar 

 green matter formed ; acd if it remain a suflicicnt time uneva- 

 porated, light-green fibres grow across each other in every 

 ditectiou through the fluid, which under these circumstances 

 retains its freshness and limpidity. The simple confervoid 

 plants, to the presence of which this appearance is due, are 

 performing here, on a small scale, similar functions to those that 

 are incessantly operating upon a larger scale in the ditches, 

 stagnant ponds, lakes, and slow rivers ; they are assimilating 

 to their own support and growth those putrescent particles of 

 animal and vegetable matter, that, accumulating from time to 

 time, produce those fatal exhalations so long observed and 

 dreaded undei the names of miasma and malaria. They may 

 not, indeed are not, in all situations proportioned to the quan- 

 tity of these, but must always act as a powerful check to the 

 increase of the evil ; and the more so, owing to the abundance 

 of oxygen gas which many of them evolve under exposure to 

 the sun. 



The influence of the sea-weeds upon their natural element 

 is probably similar to that observed of the fresh- water species. 

 This vast body of water, abounding in animal life, would, by 

 the natural exuvia of its iohabitants, soon become inca- 

 pable of supporting their existence ; but independent of this, 

 it is the grasd cesspool of the earth, receiving on every side 

 into its mighty basin all that is most noxious to the dwellers 

 of the land : every tide sweeps nuipance from its shores; every 

 river bears, with ceaseless current, its tribute of offal to this 

 general reservoir, acting as the scavenger as well as the fertili- 

 zer of the country along which it flows. How admirably are 



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