Remarlcs on the Impregnation of Plants. 309 



The comparatively recent discoveries of Amici, Adolphe Brong- 

 niart, Mirbel, and Brovi^n, 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, and 

 afterwards clearly established by Linnaeus, 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 rudimentary 

 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. 

 These 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 g-enerally 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- 

 ture of the unimpregnated ovule; Mim. sur la giniration et le diveloppement de 

 Vembryon, tf-c. by Ad. Brongniart in the 12th vol. of the Annales des Sciences 

 Naturelles; and, particularly, Nouvelles recherches sur la structure et le developpe- 

 ment de Vovule vegetal, by Mirbel, in the 17th vol. of the same work. The sub- 

 stance of these memoirs will be found in the more recent elementary botanical 

 works. 



