IN ORCrilDEiE AND ASCLEPIADEjE. 541 



course of the tubes is not at all impeded, they are very 

 nearly or altogether straight. 



The two most important facts stated in the present 

 communication are; first, the production of tubes not 

 directly emitted from the grains of pollen, but apparently 

 generated by them ; and, secondly, the introduction of one 

 or sometimes more than one of those tubes into the fora- 

 men of the ovulum, the point corresponding with the 

 radicle of the future embryo. 



The principal points remaining to be examined, and 

 which we may hope, by careful investigation, to ascertain, 

 are the precise state of the ovulum at the moment of its 

 contact with the tube, and the immediate changes conse- 

 quent to that contact. 



Supplementary Note. cr-w 



Since the paper on Pecundation in Orchidese and Ascle- 

 piadese was read before the Society, and a Pamphlet con- 

 taining all its more important statements was distributed 

 in the beginning of November, 1831,^ two essays have ap- 

 peared on the same subject. The first on both families by 

 M. Adolphe Brongniart, in the numbers of the Annates des 

 Sciences Naturelles for October and November, 1831, but 

 which were not published until January and Pebruary, 

 1832; the second, by Dr. Ehrenberg, on Asclepiadese 

 alone, in the Transactions of the Royal Academy of Sciences 

 of Berlin, before which it was read in November, 1831. 



M. Brongniart's statements respecting ORCHiDEiE to a 

 great extent agree with those of my essay. They differ, 

 however, in the following important points : 



1st, He does not seem to be aware of the operation of 

 insects in the fecundation of this family. 



2ndly, He considers the mucous cords in the cavity of 

 the ovarium (first seen by M. du Petit Thouars, with 

 whose observations he seems to be entirely unacquainted), 



' I may also refer to an excellent abstract of the Paper which appeared on 

 the 1st of December, 1831, in the Philos. Mag. and Annals of Philosophy, 



