CHAP. V. HETEROSTYLED DIMORPHIC PLANTS. 223 



in one out of a lot of illegitimate long-styled plants; 

 and in the case of Mr. Duck's seedlings, long-styled 

 plants, only slightly deviating from the normal state, 

 as well as equal-styled plants were produced from the 

 same self-fertilised parent. The position of the sta- 

 mens in their proper place low down in the tube of 

 the corolla, together with the small size of the pollen- 

 grains, show, firstly, that the equal-styled variety is a 

 modification of the long-styled form, and, secondly, that 

 the pistil is the part which has varied most, as indeed 

 was obvious in many of the plants. This variation is 

 of frequent occurrence, and is strongly inherited when 

 it has once appeared. It would, however, have pos- 

 sessed little interest if it had consisted of a mere 

 change of structure; but this is accompanied by modi- 

 fied fertility. Its occurrence apparently stands in 

 close relation with the illegitimate birth of the parent- 

 plant; but to this whole subject I shall hereafter 

 recur. 



PRIMULA AURICULA. 



Although I made no experiments on the illegitimate 

 offspring of this species, I refer to it for two reasons: 

 First, because I have observed two equal-styled plants in 

 which the pistil resembled in all respects that of the long- 

 styled form, whilst the stamens had become elongated as in 

 the short-styled form, so that the stigma was almost sur- 

 rounded by the anthers. The pollen-grains, however, of 

 the elongated stamens resembled in their small size those 

 of the shorter stamens proper to the long-styled form. 

 Hence these plants have become equal-styled by the in- 

 creased length of the stamens, instead of, as with 'P. Sinen- 

 sis, by the diminished length of the pistil. Mr. J. Scott 

 observed five other plants in the same state, and he shows * 

 that one of them, when self-fertilised, yielded more seed 

 than an ordinary long- or short-styled form would have 

 done when similarly fertilised, but that it was far inferior 



* ' Journal Proc. Linn. Soc.,' viii. (1864), p. 91. 



