72 MR. DARWIN ON TIIE EXISTENCE OF TWO FORMS 
the statement that the two forms are produced in about equal 
numbers. ‘The first thirty-four plants were kept under a net 
which excluded insects. I fertilized heteromorphically fourteen 
long-styled flowers with pollen from the short-styled, and got 
eleven fine seed-capsules ; these contained on an average 8:6 seeds 
per capsule, but only 5:6 were apparently good. It may be well to 
state that ten seeds is the maximum possible production for a 
capsule, and that our climate cannot be very favourable to this 
North-African plant. On three occasions I fertilized homomor- 
phically the stigmas of altogether nearly a hundred flowers (but 
did not separately mark them) with their own pollen, but taken 
from separate plants, so as to prevent any possible ill effects 
from close interbreeding; and many other flowers were produced, 
which, as before stated, would get plenty of their own individual 
pollen; yet from all these flowers, borne by the seventeen long- 
styled plants, only three capsules were produced; one of these in- 
cluded no seed, and the other two together gave only five good 
seeds. Nor do I feel at all sure that this miserable product of the 
two half-fertile capsules from the seventeen plants, each of which 
must have produced at least fifty or sixty flowers, is really the re- 
sult of their fertilization by their own pollen; for I made a great 
mistake in keeping the two forms under the same net, with their 
branches often interlocking, and it is surprising that a greater 
number of flowers were not accidentally fertilized. 
Of the short-styled flowers I fertilized heteromorphically twelve 
with the pollen of the long-styled (and to make sure of the result 
I previously castrated the majority), and obtained seven fine seed- 
capsules. These included an average of 7:6 seeds, but of apparently 
good seed only 43 per capsule. At three separate times I ferti- 
lized homomorphically nearly a hundred flowers with their own- 
form pollen, taken from separate plants; and numerous other 
flowers were produced, many of which must have received their 
own pollen. From all these flowers borne on the seventeen plants, 
only fifteen capsules were produced, of which only eleven con- 
tained any good seed, on an average 4/2 per capsule. As remarked 
in the ease of the long-styled plants, some even of these capsules 
were perhaps the product of a little pollen accidentally fallen 
from the flowers of the other form. Nevertheless the short- 
styled plants seem to be slightly more fertile with their own 
pollen, in the proportion of fifteen capsules to three, than the 
long-styled: the real proportional excess in fertility is probably 
a little greater, as the short-styled flowers, when not disturbed, do 
