of a Hybrid Digitalis. 267 



the most striking circumstance which we have hitherto noticed in 

 their external characters, is the perfect identity in size and shape 

 both of their pollen and of their ovules. As the respective organs 

 which contain these bodies, viz. the anthers and the ovaria, are 

 each proportionate to the different sizes of the three flowers them- 

 selves, it is evident that a flower of lutea must have much less 

 pollen and many fewer ovules than one of purpurea, which in 

 fact the most casual observation is sufficient to shew. The ovules 

 of the hybrid also are about intermediate in number to those 

 produced by the parents. It will be a subject worthy of future 

 investigation, to determine whether one condition necessary for 

 securing the hybridity of two species, require their pollen and 

 ovules to be of the same, or of nearly the same dimensions. Ex- 

 cept in the above instances, and in the very peculiar shape of 

 the stigma, all the other external characters of the hybrid ap- 

 pear to be precisely intermediate between those of its parents. 

 The chief physiological difference observable in the external 

 economy of the organs of fructification seems to reside in the 

 fall of the corolla, which in the parents does not take place 

 till after the anthers have discharged their pollen and become 

 perfectly withered, whereas in the hybrid the corolla falls before 

 the anthers on the shorter stamens have burst, and when even 

 those on the longer pair, although opened, have hardly parted 

 with their pollen, and have not as yet become in the least withered. 

 The style and stigma of all three appeared to comport themselves 

 alike, that is to say, they all began to wither soon after the fall 

 of the corolla. 



I, L 2 



