Book I. PROPAGATION OF THE SPECIES. 253 



a distance from their place of growth, merely by their attaching themselves to the bodies of such animals 

 as may happen accidentally to come in contact with the plant, in their search after food ; the hooks or hairs 

 with which one part or other of the fructification is often furnished, serving as the medium of attachment, 

 and the seed being thus carried about with the animal till it is again detached by some accidental cause, and 

 at last committed to the soil. This may be exemplified in the case of the Bldens and A/yosbtis, in which 

 the hooks or prickles are attached to the seed itself; or in the case of Galium Sparine and others, in which 

 they are attached to the pericarp; or in the case of the thistle and the burdock, in which they are attached 

 to the general calyx. Many seeds are dispersed by animals in consequence of their pericarps being used 

 as food. This is often the case with the seeds of the drupe, as cherries and sloes, and with the berries of 

 the hawthorn, wliich birds often carry away till they meet with some convenient place for devouring the 

 pulpy pericarp, and then drop the stone into the soil. And so also fruit is dispersed that has been hoarded 

 for the winter, though even with the view of feeding on the seed itself, as in the case of nuts hoarded up 

 by squirrels, which are often dispossessed by some other animal, which, not caring for the hoard, scatters 

 and disperses it. Sometimes the hoard is deposited in the ground itself, in which case part of it is generally 

 found to take root and to spring up into plants ; though it has been observed tliat the ground squirrel often 

 deprives the kernel of its germ before it deposits the fruit it collects. Rooks have been also observed to 

 lay up acorns and other seeds in the holes of fence-posts, which being either forgot or accidentally thrust 

 out, fall ultimately into the earth and germinate. But sometimes the seed is even taken into the stomach 

 of the animal, and afterwards deposited in the soil, having passed through it unhurt. This is often the 

 case with the seed of many species of berry, such as the mistletoe, which the thrush swallows and 

 afterwards deposits upon the boughs of such trees as it may happen to alight upon. The seeds of the Lo- 

 ranthus americanus, another parasitical plant, are said to be deposited in like manner on the branches of 

 the Cocc(')loba grandiflbra and other lofty trees ; as also the seeds of Phytolacca decindra, the berries of 

 which are eaten by the robin, thrush, and wild pigeon. And so also the seeds of currants or roans are 

 sometimes deposited, after having b-en swallowed by blackbirds or other birds, as may be seen by ob- 

 serving a currant bush or young roan tree growing out of the cleft of another tree, where the seed has been 

 left, and where there may happen to have been a little dust collected by way of soil ; or where a natural 

 graft may have been effected by the insinuation of the radicle into some chink or cleft. It seems indeed 

 surprising that any seeds should able to resist the heat and digestive action of the stomach of animals; 

 but it is undoubtedly the fact. Some seeds seem even to require it. The seeds of MagnJ.ha gla6ca, which 

 have been brought to this country, are said generally to have refused to vegetate till atter undergoing this 

 process, and it is known that some seeds will bear a still greater degree of heat without any injury. Spal- 

 lanzani mentions some seeds that germinated after having been boiled in water : and Du Hamel gives an 

 account of some others that germinated even after having been exposed to a degree of heat measuring 

 2330 of Fahrenheit. In addition to the instrumentality of brute animals in the dispersion of the seed might 

 be added also that of man, who, for purposes of utility or of ornament, not only transfers to his native soil 

 seeds indigenous to the most distant regions, but sows and cultivates them with care. " A farmer in the 

 west of Scotland has been in the practice, for some years, of feeding his cows upon potato-apples, and 

 using their dung, and raising seedling plants from it the seeds; having passed tlirough the stomach of the 

 cow, without having undergone such a change as to prevent them from vegetating. " {Note of Mr. Cleghorn, 

 Ed. of the Edinburgh Farm. Mag.) 



1644. The agency of winds is one of the most effective modes of dispersion instituted by nature. Some 

 seeds are fitted for this mode of dispersion from their extreme minuteness, such as those of the mosses, 

 lichens and Fungi, which float invisibly on the air, and vegetate wherever they happen to meet with a 

 suitable soil. Others are fitted for it by means of an attached wing, as in the case of the fir tree and 

 Liriodendron tulipifera, so that the seed, in falling from the cone or capsule, is immediately caught by the 

 wind, and carried to a distance. Others are peculiarly fitted for it by means of their being furnished with 

 an aigrette or down, as in the case of the dandelion, goat's. beard, and thistle, as well as most plants of the 

 class Syngenfesia ; the down of which is so large and light in proportion to the seed it supports, that it is 

 wafted on the most gentle breeze, and often seen floating through the atmosphere in great abundance at 

 the time the seed is ripe. Some have a tail, as in Clematis Vitalba. Others are fitted for this mode of 

 dispersion by means of the structure of the pericarp, which is also wafted along with them, as in the case of 

 StaphylfeatrifoUa, the inflated capsule of which seems as if obviously intended thus to aid the dispersion 

 of the contained seed, by its exposing to the wind a large and distended surface with but little weight ; and 

 so also in the case of the maple, elm, and ash, the capsules of which are furnished, like some seeds, with 

 a membranous wing, which when they separate from the plant the wind immediately lays hold of and 

 drives before it. 



1645. The instrumentality of streams, rivers, and currents of the ocean, is a further means adopted by 

 nature for the dispersion of the seeds of vegetables. The mountain-stream or torrent washes down to 

 the valley the seeds which may accidentally fall into it, or which it may happen to sweep from its banks 

 when it suddenly overflows them. The broad and majestic river, winding along the extensive plain, and 

 traversing the continents of the world, conveys to the distance of many hundreds of miles the seeds that 

 may have vegetated at its source. Thus the southern shores of the Baltic are visited by seeds which grew 

 in the interior of Germany, and the western shores of the Atlantic by seeds that have been generated in 

 the interior of America. But fruits indigenous to America and the "West Indies have sometimes been 

 found to be swept along by the currents of the ocean to the western shores of Europe, and even on the 

 coasts of Orkney and Shetland. Fruits of Mim5sa scandens, Stizolobium pruriens, Guilandina Bonduc, 

 and Anacardium occident^le, or cashew nut, have been thus known to be driven across the Atlantic 

 to a distance of upwards of 2000 miles ; and although the fruits now adduced as examples are not such 

 as could vegetate on the coast on which they were thrown, owing to soil or climate, yet it is to be 

 believed that fruits may have been often thus transported to climates or countries favourable to their 

 vegetation. 



1646. Propagation by gems. Though plants are for the most part propagated by means of seeds, yet 

 many of them are propagated also by means of gems ; that is, bulbs and buds. 



1647. The caulinary bulb is often the means of the propagation of the species : it generally appears in 

 the axils of the leaves, as in Dentaria bulbifera and Lilium bulbiferum ; or between the spokes of their 

 umbels, as in A'Wmm canadense; or in the midst of the spike of flowers, as in Polygonum viviparum and 

 Pbaalpina. As plants of this last kind are mostly alpine, it has been thought to be an institution or 

 resource of nature, to secure the propagation of the species in situations where the seed may fail to ripen. 



1648. The bud, though it does not spontaneously detach itself from the plant and form a new individual, 

 will yet sometimes strike root and develope its parts if carefully separated by art and planted in the earth : 

 but this is to be understood of the leaf-bud only, for the flower-bud, according to Mirbel, if so treated, 

 always perishes. 



1619. Propagation try the leaves. The species may sometimes be propagated even by means of the leaves, 

 as in the aloe, Xylophy 11a, sea-onion, and some species of ^\um ; which if carefully deposited m the soil 

 will grow up into new plants, by virtue, no doubt, of some latent gem contained in them. The Fungi and 

 lichens, according to Gajrtner, are all gemmiferous, having no sexual organs, and no pollen impregnating 

 a germ. In the genus Lycoperdon, the gelatinous substance that pervades the cellular tissue is converted 

 into a proliferous powder ; in Clav^ria, the fluid contained in the cavities of the plant is converted into a 

 proliferous powder also; and in the agarics, //ypnum, and .Solfetus, vesicles containing soboliferous 

 granules are found within the lamella;, pores, or tubes. Hedwig, on the contrary, ascribes to the Fungi a 

 sexual apparatus, and maintains that the pollen is lodged in the volva : but here it is to be recollected, as 

 in the cases of the scutella of the litchens, that all Fungi are not furnished with a volva, and consequently 

 not furnished with pollen. The Conft^rvse and U'\\'?e, together with the genera Bliisia and Riccia are 



