84 HETEEOSTYLED DIMOEPHIC PLANTS. Chap. IIL 



with the short-styled plants. The one which grew 

 close to the long-styled plant produced ninety-four 

 imperfectly fertilised capsules containing a multitude 

 of bad seeds, with a moderate number of good ones. 

 The two other short-styled plants growing together 

 were 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 more 

 fertile with their own pollen than are the long-styled, 

 and we shall immediately see that this probably is the 

 case. But I suspect that the difference in fertility be- 

 tween the two forms was in this instance 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. 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 sucking the flowers ; and these 

 insects, though not visiting the flowers with anything 

 like the regularity of bees, would carry a little poUen 

 from one form to the other, especially when growing 

 near together; and the stigmas of the short-styled 

 plants, diverging within the tube of the corolla, would 

 be more likely than the upright stigmas of the long- 

 styled plants, to receive a small quantity of pollen if 

 brought to them by small insects. Moreover from the 

 greater number of the long-styled than of the short- 

 styled plants in the garden, the latter would be more 

 likely to receive pollen from the long-styled, than the 

 loug-styled from the short-styled. 



In 1862 I raised thirty-four plants of this Linum in a 

 hot-bed ; and these consisted of seventeen long-styled 

 and seventeen short-styled forms. Seed sown later in the 



