OV FECUNDATION. 



81 



If tixe gills are next examined in the ssime man- 

 ner, and about tlie same time, there will be found 

 resting on tlieir edges or surface a number of 

 small tender cylindrical substances, some of 

 which ai-e surmounted by a small globule, while 

 others are without this. These he conjectures 

 to be the stj'les and summits. Similar substances 

 may be detected on the other families of the 

 same tribe ; but from the extreme minuteness of 

 these parts, and from their strong likeness to 

 the down with which the inner organs of vege- 

 tables are covered, it is easy to perceive how very 

 difficult it must be to decide upon their true 

 character. BuUiard docs not pretend to have 

 discovered, and does not think it necessary that 

 there should exist in the fungi, organs exactly 

 corresponding to the stamens and pistils of con- 

 spicuous flowers, but only organs analogous to 

 them, and capable of perfonuing similar func- 

 tions, the ground of which opinions he has illus- 

 trated in his theory of the fractification of the 

 fungi, and rendered at least as tenable as any 

 that have been taken up against him. Gaertner 

 is also of opinion that the fungi do not in any 

 case produce perfect seeds, but are propagated 

 like fuci, by that peculiar species of gem which 

 we have already alluded to. However this may 

 be, one thing is certain, that the fungi as well as 

 the other simpler plants, do propagate their 

 species by gems or seeds. In the agaricus and 

 other similar mushrooms, this receptacle is the 

 gUls, in which, by the aid of a good microscope, 

 about the time the curtain bursts, tliere may be 

 observed, on raising up a small portion of their 

 flat surface, a number of small minute granules 

 imbedded in their substance ; these granules are 

 the seeds or gems, which, in a ripened state, are 

 discharged in such numbers and with such force, 

 that a piece of white paper put under the plant 

 will soon be found covered with a fine brown 

 powder. In the boletus this receptacle is the 

 tubes. In the moulds it is the globule, sur- 

 mounting the thread-shaped pedicle or stipe ; in 

 the clavaria it is over the general surface. 



CHAP XV. 



OF FECUNDATIOX. 



The discovery of the male and female organs 

 in plants opened a new field of observation, by 

 directing attention to the mode of action which 

 they exercise upon each other. 



Until of late years, the mechanism of fecunda- 

 tion in plants was as little understood as tliat of 

 animals. It was known, however, that the female 

 organ is fecundated; that the ovules or rudiments 

 of the seeds contained in tlie ovary become fit for 



being developed, and for subsequently reproduc- 

 ing precisely similar individuals, whenever the 

 pollen, contained in the cells of the stamen, has 

 exercised its influence upon the stigma. But the 

 nature of the influence which the pollen exer- 

 cises upon the stigma was entirely unknown. 

 The recent inquiries of various observers, have 

 thrown much light on this important question, 

 and have shown that, in plants, fecundation 

 appears to have the same mechanism as in ani- 

 mals. 



Here, as in her other works, we find occasion 

 to admire the wisdom of Nature, and the per- 

 fection which she gives to the instruments which 

 she employs. Animals, possessed of the faculty 

 of moving, and able to shift at will from one 

 place to another, generally have the organs of 

 generation separated on two individuals of the 

 same species. The male, at determinate periods, 

 excited by an internal feeling, seeks out and ap- 

 proaches the female. Plants, on the other hand, 

 destitute of the locomotive faculty, irrevocably 

 fixed to the place in which their existence has 

 commenced, and destined to grow and die in it, 

 generally have the two sexes combined, not only 

 in the same individual, but in most cases even 

 in the same flower. Thus hermaphrodism is 

 very common in plants. 



There are some, however, which might at first 

 sight seem less favourably situated, and in which 

 fecundation might appear to be left by nature 

 to chance, such as the monoecious and dioecious 

 plants. In them the two sexual organs are 

 separated from each other, and often removed to 

 great distances. But here also we find reason 

 to admire the wisdom of Nature. As in animals 

 the fecundating substance is fluid, the male organ 

 must in them act directly upon the female organ 

 before fecundation can be effected. If it had 

 been of the same nature in plants as in animals, 

 fecundation would dotibtless have experienced 

 the greatest obstacles in the monoecious and di- 

 oecious species. But in vegetables the pollen 

 exists in the form of a powder, whose particles 

 are light and extremely minute, so that they 

 can be transported in the atmosphere to distances 

 which are often inconceivable. 



It may also be remarked that, in monoecious 

 plants, the male flowers are generally situated 

 at the upper part of the plant, so that the pollen, 

 on escaping fi-om the cells of the anther, falls 

 naturally, and by its own weight, upon the 

 female flowers, which are placed lower. 



Hennaphrodite flowers are unquestionably 

 those in which all the circumstances are most 

 favourable to fecundation, the two sexual organs 

 being in them placed in the same flower. The 

 function commences the moment the cells of the 

 anther open to allow the pollen to escape. 

 There are plants in which the adherency of the 

 anthers permits fecundation to take place before 

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