220 PRIMULA VERIS. CHAP. VI. 



year, by which time they ought to have become accustomed to 

 growing out of doors, so that they must have possessed a weak 

 constitution. 



Under these circumstances, it seemed advisable to ascertain 

 what would be the effect of legitimately crossing long-styled 

 plants of the fourth illegitimate generation with pollen taken from 

 non-related short-styled plants, growing under different con- 

 ditions. Accordingly several flowers on plants of the fourth 

 illegitimate generation (i.e., great-great-grandchildren of plants 

 which had been legitimately fertilised), growing vigorously in pots 

 in the greenhouse, were legitimately fertilised with pollen from 

 an almost wild short-styled cowslip, and these flowers yielded 

 some fine capsules. Thirty other flowers on the same illegi- 

 timate plants were fertilised with their own pollen, and these 

 yielded seventeen capsules, containing on an average thirty-two 

 seeds. This is a high degree of fertility ; higher, I believe, than 

 that which generally obtains with illegitimately fertilised long- 

 styled plants growing out of doors, and higher than that of the 

 previous illegitimate generations, although their flowers were 

 fertilised with pollen taken from a distinct plant of the same 

 form. 



These two lots of seeds were sown (for they will not germinate 

 well when placed on bare sand) on the opposite sides of four 

 pots, and the seedlings were thinned, so that an equal number 

 were left on the two sides. For some time there was no marked 

 difference in height between the two lots ; and in Pot III., Table 

 XCIIL, the self-fertilised plants were rather the tallest. But by 

 the time that they had thrown up young flower-stems, the 

 legitimately crossed plants appeared much the finest, and had 

 greener and larger leaves. The breadth of the largest leaf on 

 each plant was measured, and those on the crossed plants were 

 on an average a quarter of an inch (exactly '28 of an inch) 

 broader than those on the self-fertilised plants. The plants, 

 from being too much crowded, produced poor and short flower- 

 stems. The two finest on each side were measured ; the eight 

 on the legitimately crossed plants averaged 4 08, and the eight on 

 the illegitimately self-fertilised plants averaged 2 '93 inches in 

 height; or as 100 to 72. 



These plants after they had flowered were turned out of their 

 pots, and planted in fairly good soil in the open ground. In 

 the following year (1870), when in full flower, the two tallest 

 flower -stems on each side were again measured, as shown in the 



