Remarks on the Impregnation of Plants. 309 
The comparatively recent discoveries of Amici, Adolphe Brong- 
niart, Mirbel, and Brown, having invested the subject of vegetable 
reproduction with unusual interest, I was naturally led to study the 
memoir of M. Corda with particular attention. The researches here 
communicated to the scientific world are the last, though by no means 
the least, of a series of discoveries on this recondite subject, which, 
taken together, may be safely said to form the most important con- 
tribution ever made in vegetable physiology. I had prepared a 
translation of this paper for my own private use ; but, supposing that 
it would be generally interesting, I have been induced to lay it before 
the Lyceum. I have thought it advisable, moreover, to premise a 
cursory account of the progress of discovery respecting the fecunda- 
tion of flowering plants, for the purpose of rendering the subjoined 
memoir more generally intelligible to those who are not particularly 
conversant with the present state of botanical science. 
Impregnation, in flowering plants, essentially consists in the pro- 
duction of an embryo or rudimentary plant within the ovule,* or 
body destined to become the seed. Since the office of the stamens 
in vegetable reproduction was indicated by Grew and Ray, an 
afterwards clearly established by Linneus, it has been well known 
that unless some grains of pollen come in contact with the stigma, 
impregnation does not take place. The seed-vessel may, indeed, 
continue to grow and ripen in the absence of pollen, and the con- 
tained ovules attain the size, texture, and (the embryo excepted) 
the structure of well-formed seeds; but in such cases a ru 
plant, which is the essential part of the seed, is never produced. 
Respecting the immediate origin of the embryo in the animal king- 
dom, it is well known that three different hypotheses, being all that 
the nature of the case admits of, were advanced at an early period. 
Thesé several hypotheses have been extended by analogy to the 
vegetable kingdom. According to one view a germ furnished by 
* The reader is supposed to be acquainted generally with the structure of the 
ovule, a subject upon which the limits of the present remarks will not allow me to 
enter, except to indicate the sources from which the requisite knowledge may be 
obtained, viz: R Brown’s-paper on the genus Kingia, with remarks on the struc- 
de 
Naturelles; and, particularly, Nowvelles recherches sur la structure et le de 
ment de Vovule végétal, by ee in the 17th vol. of the same work. 
Stance of these memoirs will be found in the more recent elementary botanical 
works. 
