Book I. PROPAGATION OF THE SPECIES. 251 



stigma exhibits also similar symptoms of decay, and the style itself often perishes. The part* oontlguoug 

 to the flower, such as the bractes and floral leaves, are sometimes also affected j and finally the whole 

 plant, at least in the case of annuals, begins to exhibit indications of decay. But while the flower wither* 

 and falls, the ovary is advancing to perfection, swelling and augmenting in size, and receiving now all the 

 nutriment by which the decayed parts were formerly supported. Its color begins to assume a deeper and 

 richer tinge; its figure is also often altered, and new parts are even occasionally added wings, crests, 

 prickles, hooks, bloom, down. The common receptacle of the fruit undergoes also similar changes, becom- 

 ing sometimes large and succulent, as in the fig and strawberry ; and sometimes juiceless and indurated, 

 as in compound flowers. 



leO.'i. Internal changes. If the ovary is cut open as soon as it is first discoverable in the flower, it pre- 

 sents to the eye merely a pulpy and homogeneous mass. But if it is allowed to remain till immediately 

 before the period of its impregnation, it will now be found to be divisible into several distinct parts, exhi- 

 biting an apj)aratus of cells, valves, and membranes, constituting the pericarp, and sometimes the external 

 coats of the seed. In this case the umbiUcal cord is also to be distinguished ; but the embryo is not yet 

 visible. These changes, therefore, are to be attributed merely to the operation of the ordinary laws of 

 vegetable developement, and are not at all dependent upon impregnation. But impregnation has no 

 sooner taken place than its influence begins to be visible ; the umbilical cord, which was formerly short 

 and distended, is now generally converted into a long and slender thread. Sometimes the position of the 

 seed is altered. Before impregnation the seeds of caryophyllus aromaticus and netrosideros gummifera, 

 are horizontal ; after impregnation they become vertical. Before impregnation the magnolia seeds are 

 erect; after impregnation they become inverted and pendulous. The figure of the seed is often also 

 altered in passing from its young to its mature state ; changing from smooth to angular, from tapering to 

 oval, from oval to round, and from round to kidney-shaped. But allseeds are not brought to maturity, of 

 which the rudiments may exist in the ovary. Lagoecia and hasselquistia, produce uniformly the rudi- 

 ments of two seeds, of which they mature but one. But the principal changes resulting from impregnation 

 are operated in the seed itself, which, though previously a homogeneous and gelatinous mass, is now con- 

 verted into an organised body, or embryo. Such are the phenomena, according to the description of 

 Gajrtner, accompanying or following the impregnation of all flowers producing seeds ; exceptions occur 

 where the fecundation is spurious and incomplete ; where the ovary swells, but exhibits no traces of perfect 

 seed within, as often happens in the vine and tamus; or when barren and fertile seeds are intermingled 

 together in the same ovary. This proceeds from some defect either in the quantity or quality of the pollen; 

 but rather in the quality, as it is not' always plants having the most pollen that produce the most seeds. 

 The two stamens of the orchids fecundate 8000 seeds, and the five stamens of tobacco fecundate 900 : while 

 the 50 stamens of barringtonia, the 230 of thea, and the 80 of the caryophilli, fecundate only two or three 

 ovaries. 



Sect. IX. The Propagation of the Species. 



1606. As the life of the vegetable, like that of the animal, is limited to a definite period, 

 and as a continued supply of vegetables is always wanted for the support of animals, 

 what we call art, or nature operating by means of the animal man, has taken care to 

 institute such means as shall secure the multiplying and perpetuating of the species in 

 all possible cases. 



1607. Equivocal generation. It was long a vulgar error, countenanced even by the philosophy of the 

 times, that vegetables do often spring up from the accidental mixture of putrid water and earth, or other 

 putrid substances, in the manner of what was called the equivocal generation of animals ; or at the very 

 least, that the earth contains the principle of vegetable life in itself, which, in order to develope, it is only 

 necessary to expose to the action of the air. The former alternative of the error has been long ago re- 

 futed ; the latter has lost its hold, having been also refuted by Malpighi, who proved that the earth pro- 

 duces no plant without the intervention of a seed, or of some other species of vegetable germ deposited in 

 it by nature or by art. 



1608. Propagation by seeds. When the seed has reached maturity in the due and 

 regular course of the developement of its several parts, it detaches itself sooner or later 

 from the parent plant, either singly or along with its pericarp, and drops into the soil, 

 where it again germinates and takes root, and springs up into a new individual. Such 

 is the grand means instituted by nature for the replenishing and perpetuating of the 

 vegetable kingdom. 



1609. Dispersion of seed. If seeds were to fall into the soil merely by dropping down from the plant, 

 then the great mass of them, instead of germinating and springing up into distinct plants, would grow up 

 only to putrefy and decay ; to prevent which consequence 

 nature has adopted a variety of the most efficacious contri- 

 vances, all tending to the dispersion of the seed. The first 

 means to be mentioned, is that of the elasticity of the peri- 

 carp of many fruits, by which it opens ivhen ripe, with a sort 

 of sudden spring, ejecting the seed with violence, and throw- 

 ing it some considerable distance from the plant. This may be 

 exemplified in a variety of cases ; the seeds of oats when ripe 

 are projected from thecalyx with such violence, that in a fine 

 and dry day you may even hear them thrown out with a 

 slight and sudden snap in passing through a field that is ripe. 

 The pericarp of the Dorsiferous Ferns {Jig. 239 a.) is furnished 

 with a sort of peculiar elastic ring {b), intended, as it would 

 appear, for the very purpose of projecting the seeds. -The 

 capsules of the cucumber, geranium geum, and fraxinella, 

 discharge their seeds also when ripe with an elastic jerk. But 

 the pericarj) of impatiens, which consists of one cell with 

 five valves, exhibits perhaps one of the best examples of this 

 mode of dispersion. If it is accidentally touched when ripe 

 it will immediately burst open, while the valves, coiling 

 themselves up in a spiral form, and springing from the stem, 

 discharge the contained seeds, and scatter them all around. 

 The bursting of the pericarp of some species of pines is also 

 worthy of notice. "Die pericarp, which is a cone, remains 

 on the tree till the summer succeeding that on which it was 

 produced, the scales being still closed. But when the hot 

 weather has commenced and continued for some time, so as 

 to dry the cone thoroughly, the scales open of their own 



