IN SEVERAL SPECIES OF THE GENUS LINUM. 71 
two plants produced, before and after and at the time of the trial, 
a vast number of flowers, but the germens of not even one swelled. 
All these flowers, though their stigmas were so densely covered 
with their own pollen, were absolutely barren. 
The nine other plants, six long-styled and three short-styled, 
grew in the beds of the same flower-garden. Four of the long- 
styled produced no seed-capsules; one produced two; but the re- 
maining long-styled plant grew so close to a short-styled plant 
that their branches touched, and this produced twelve capsules, 
but they were poor. The case was different with the short-styled 
plants. The plant which grew in juxtaposition with the long- 
styled plant produced ninety-four imperfectly fertilized capsules 
containing a multitude of bad seeds, with a moderate number of 
good seeds. "The two other short-styled plants grew in a single 
clump, and were very small, being partly smothered by other 
plants; they did not stand very close to any long-styled plants, 
yet they yielded together nineteen capsules. These facts seem to 
show that the short-styled plants are far more fertile with their 
own pollen than the long-styled. We shall immediately see that 
this is the case in a slight degree. But I suspect that in this 
instance the difference in fertility between the two forms was in 
part due to a distinct cause. I repeatedly watched the flowers, 
and only once saw a humble-bee momentarily alight on one, and 
then fly away, as if it were not to its taste. If bees had visited 
the several plants, there cannot be a doubt that the four long- 
styled plants which did not produce a single capsule would have 
borne an abundance. But several times I saw small diptera suck- 
ing the flowers ; and these insects, though not visiting the flowers 
with anything like the regularity of bees, would carry a little 
pollen from one form to the other, especially when growing close 
together; and the stigmas of the short-styled plants, diverging 
within the tube of the corolla, would be more.likely than the up- 
right stigmas of the long-styled to receive a small quantity of 
pollen when brought by small insects. From the much greater 
number of long-styled than of short-styled flowers in the garden, 
evidently the short-styled would be more likely to receive some 
pollen from the long-styled, than the long-styled from the short- 
styled. 
In 1862 I raised thirty-four plants of this Linum in a hotbed; 
and these consisted of seventeen long-styled and seventeen short- 
styled forms. Seed sown later in the flower-garden yielded seven- 
teen long-styled and twelve short-styled forms, These facts justify 
