HYBRID INTERMIXTURES. 
351 
of the stigma ; my observation is, that its early destruction 
is very prejudicial to the growth of the germen and stigma, 
but that after their developement it is not usually essential. 
He observes that the corolla perishes more quickly and com- 
pletely after fecundation, and is more persistent and some- 
times withers instead of falling off, in cases of hybrid im- 
pregnation, as it does where impregnation is prevented ; but 
he seems not to have distinguished the cases of successful 
and abortive hybrid impregnation. I observe that he admits 
that the viscous juice remains on the stigma of Datura and 
Nicotiana two or three days after fecundation, which does 
not exactly agree with his theory, and seems to mark that 
the stigma has not become quite inoperative. Some days 
elapse before any other signs of fecundation appear after the 
fall of the corolla, such as the enlargement of the peduncle, or 
strengthening of its articulation, and that period seems to 
him longer in hybrid impregnation, and the interval longer 
before the seeds are vivified. Both he and Kolreuter observe 
instances, such as I have found, of false hybrid fecundation, 
producing an enlargement of the germen, or even seeds with 
an imperfect embryo or without any. They remarked, that 
they did not usually obtain the full complement of seeds 
from a hybrid impregnation, unless the affinity was very 
close. My own observation is that this circumstance de- 
pends rather on the similarity of constitution, and is by no 
means universal, for I had a pod from Crinum Capense 
fertilized by revolution, in which every ovule produced a 
seedling plant, which I never saw to occur in a case of its 
natural fecundation. He cites from Kolreuter that Datura 
metel and laevis have each about 600 seeds in a capsule ; he 
found that a capsule from one of them fertilized by the other 
contained 640, and in another case 284 ; but that Datura 
laevis by Nicotiana rustica produced only 108 seeds, which 
were however apparently perfect and provided with an em- 
bryo ; but I utterly repudiate the probability of that impreg- 
nation, of which he has not published the ultimate result. 
In Gaertncr’s list, I find Convolvulus sepium by Ipomoea 
purpurea (the Convolvulus major of nurserymen) 8 experi- 
ments failed ; the converse 10 failed. Iporn. purpurea by 
Convolvulus tricolor 6 failed ; 1 successful, which I greatly 
doubt. Datura laevis by Metel, 4 failed and 4 succeeded ; 
by Hyoscyamus all failed ; by Nicotiana macrophylla 3 failed ; 
1 succeeded ; by Nicot. rustica 1 failed, 1 succeeded. Datura 
