2l6 NEW ORGAN IN SEED*;. 



seeds in the pericarp, and that the point by which these are 

 attached alwa)'s determines the direction of the radicle*. 

 Point of attach- It is known too, that the point of attachment of an ovu- 

 oTu'l im ^ ^""^ ^^ ^^^^ umbilicus, with which an infinite number of ves- 

 sels, destined to form at first the vascular organization of all 

 parts of the seed, and then to convey nourishment to it 

 both before and after fecundation, inosculate in the form of 

 a cord of p^reater or less length: but how is this fecundation 

 effected ? by what way can it reach and penetrate the ovula. 

 Fecundation, rpj^j^ -^ certainly an important question to be solved, and on 

 Common opi- which, to this day, scarcely any thing has been said. The 

 it^ ' ° opinion most generally received is, that the prolific vapour 



descends from the papillce of the stigma into the placenta, 

 and transmits the fecundation to the embryo through the 

 Not probable, umbilicus. But 1 would here appeal to reason, and ask 

 whether it be conceivable, that the same vessels, and the 

 same aperture on the ovula, can fulfil two such different 

 functions as those of conveying to the embryo nutrition and 

 fecundation, the sources of which are so opposite. 

 Another organ Such was the reasoning that induced me, to examine 

 ^^drf^*^ ^^^^^ d carefully whether some other organ beside the nourishing 

 un;ibilicus did not exist in the ovulum. It was not long be- 

 fore I discovered what I at first suspected: for on the first 

 dissection I observed near the cicatricula of the hilura an- 

 other aperture, which I could not avoid immediately con- 

 sidering as the organ, by which the intromission of the fer- 

 tilizing vessels must take place. 

 This organ al- This organ, as I have satisfied myself by more than twelve 

 ways as near as hundred dissections of seeds with one and two cotyledons, 

 gyg is always placed as close as possible to the hilum at the 



time of fecundation ; and if it sometimes recede from it af- 



Direction of * When 1 say, that the radicle is always directed toward the umbilicus, 



the radicle. I mean the umbilicus of the internal membrane. This membrane, to 

 which the direction of the embryo is always subordinate, may sometimes 

 be inverted in the outer integument, as in the louscwort and eyebright: 

 for as there are seeds inverted in the pericarp, for instance in the plum 

 »nd the hazel nut, so it happens, that the interior membrane is inverted 

 in the outer. This organization requires, that the umbilical cord, after 

 having passed through the exterior omphalodes, should creep betvyeen 

 the two coats, to inosculate at the base of the interior membrane, which 

 in this case is opposite to that of the exterior. 



terward 



