CHAP. VI. EQUAL-STYLED VARIETY. 223 



form to another, as in the common cowslip. From the stigma 

 and anthers standing nearly on the same level, the flowers are 

 perfectly self-fertile when insects are excluded. Owing to the 

 fortunate existence of this variety, it is possible to fertilise its 

 flowers in a legitimate manner with their own pollen, and to 

 cross other flowers in a legitimate manner with pollen from 

 another variety or fresh stock. Thus the offspring from both 

 unions can be compared quite fairly, free from any doubt from 

 the injurious effects of an illegitimate union. 



The plants on which I experimented had been raised during 

 two successive generations from spontaneously self-fertilised 

 seeds produced by plants under a net ; and as the variety is 

 highly self-fertile, its progenitors in Edinburgh may have been 

 self-fertilised during some previous generations. Several flowers 

 on two of my plants were legitimately crossed with pollen from 

 a short-styled common cowslip growing almost wild in my 

 orchard ; so that the cross was between plants which had been 

 subjected to considerably different conditions. Several other 

 flowers on the same two plants were allowed to fertilise them- 

 selves under a net ; and this union, as already explained, is a 

 legitimate one. 



The crossed and self-fertilised seeds thus obtained were sown 

 thickly on the opposite sides of three pots, and the seedlings 

 thinned, so 'that an equal number were left on the two sides. 

 The seedlings during the first year were nearly equal in 

 height, excepting in Pot III., Table XCIV., in which the self- 

 fertilised plants had a decided advantage. In the autumn the 

 plants were bedded out, in their pots; owing to this circum- 

 stance, and to many plants growing in each pot, they did not 

 flourish, and none were very productive in seeds. But the 

 conditions were perfectly equal and fair for both sides. In the 

 following spring I record in my notes that in two of the pots 

 the crossed plants are " incomparably the finest in general 

 appearance," and in all three pots they flowered before the self- 

 fertilised. When in full flower the tallest flower-stem on each 

 side of each pot was measured, and the number of the flower- 

 stems on both sides counted, as shown in the following table. 

 The plants were left uncovered, and as other plants were growing 

 close by, the flowers no doubt were crossed by insects. When 

 the capsules were ripe they were gathered and counted, and 

 the result is likewise shown in the following table : 



