IN ORCHIDE^ AND ASCLEPIADE^. 537 



ADDITIONAL OBSEEVATIONS ON THE MODE OF [739 

 FECUNDATION IN ORCHIDEtE. 



Read June Sth, 1832. 



The following additions to the Paper which was communi- 

 cated to the Society in November last, on the Sexual 

 Organs and Mode of Fecundation in Orchidese and Ascle- 

 piadesBj relate entirely to the former family. 



In the essay itself I had ascertained from the examina- 

 tion of a considerable number of species belonging to 

 different tribes of Orchidese, that in the expanded flower of 

 this family, however long it had remained in that state, no 

 appearance whatever existed of those tubes which form 

 the mucous cords, either in the tissue of the stigma or in 

 the cavity of the ovarium, anterior to the application of the 

 pollen to the stigma ; and that in all cases where pollen 

 had been applied to that organ and enlargement of the 

 ovarium had followed, the mucous cords were to be found. 



From these facts I had concluded that the tubes forming 

 the cords were entirely and directly produced from the 

 grains of pollen ; and hence I accounted for the cohesion 

 of the pollen into masses, and its frequent application in 

 that state to the stigma. 



Some cases, however, in which a few lobules or even 

 grains of pollen only were observed on the stigmata of im- 

 pregnated flowers, had led me to express myself doubtfully 

 on this point. And since my paper was read, I have had 

 opportunities of making several observations and experi- 

 ments which prove that the application of a very small 

 portion of a pollen mass to the stigma is sufficient for the 

 production of mucous cords of the ordinary size in the 

 cavity of the ovarium. 



My observations on this point and on the gradual pro- [7« 

 duction and descent of these cords have been made chiefly 

 on Bonatea speciosa, perhaps the most favourable subject 

 for such experiments in the whole family. 



