42 HETEROSTYLED DIMORPHIC PLANTS. Chap. I. 



spontaneously self-fertile, five long-styled plants were 

 protected by me from insects; and they bore up to a 

 given period 147 flowers which set 63 capsules; but 

 many of these soon fell off, showing that they had not 

 been properly fertilised. At the same time five short- 

 styled plants were similarly treated, and they bore 116 

 flowers which ultimately produced only seven capsules. 

 On another occasion 13 protected long-styled plants 

 yielded by weight 35.9 grains of spontaneously self- 

 fertilised seeds. At the same time seven protected 

 short-styled plants yielded only half-a-grain weight of 

 seeds. Therefore the long-styled plants yielded nearly 

 34 times as many spontaneously self -fertilised seeds as 

 did the same number of short-styled plants. The chief 

 cause of this great difference appears to be, that when 

 the corolla of a long-styled plant falls off, the anthers, 

 from being situated near the bottom of the tube, are 

 necessarily dragged over the stigma and leave pollen 

 on it, as I saw when I hastened the fall of nearly 

 withered flowers; whereas, in the short-styled flowers, 

 the stamens are seated at the mouth of the corolla, 

 and in falling off do not brush over the lowly-seated 

 stigmas. Hildebrand likewise protected some long- 

 styled and short-styled plants, but neither ever yielded 

 a single capsule. He thinks that the difference in our 

 results may be accounted for by his plants having been 

 kept in a room and never having been shaken; but 

 this explanation seems to me doubtful; his plants were 

 in a less fertile condition than mine, as shown by 

 the difference in the number of seeds produced, and it 

 is highly probable that their lessened fertility would 

 have interfered with especial force with their capacity 

 for producing self-fertilised seeds. 



