THE MUTATION THEORY 317 



to be of some utility after slight showers, but was observed to be a 

 source of weakness during wet weather in my garden, preventing the 

 leaves from drying. Whether the laevifolia would do better under 

 such circumstances, I have, however, omitted to test. 



The flowers of the laevifolia are also in a slight degree different 

 from those of lamarckiana. The yellow color is paler and the petals 

 are smoother. Later, in the fall, on the weaker side branches these 

 differences increase. The laevifolia petals become smaller and are 

 devoid of the emargination at the apex, becoming ovate instead of 

 obcordate. This shape is often the most easily recognized and most 

 striking mark of the variety. In respect to the reproductive organs, 

 the fertility and abundance of good seed, the laevifolia is by no means 

 inferior or superior to the original species. 



0. brevistylis, or the short-styled evening-primrose, is the most 

 curious of all my new forms. It has very short styles, which bring 

 the stigmas only up to the throat of the calyx-tube, instead of upwards 

 of the anthers. The stigmas themselves are of another shape, more 

 flattened and not cylindrical. The pollen falls from the anthers 

 abundantly on them, and germinates in the ordinary manner. 



The ovary which in lamarckiana and in all other new forms is 

 wholly underneath the calyx-tube, is here only partially so. This tube 

 is inserted at some distances under its summit. The insertion divides 

 the ovary into two parts: an upper and a lower one. The upper part 

 is much reduced in breadth and somewhat attenuated, simulating a 

 prolongation of the base of the style. The lower part is also reduced, 

 but in another manner. At the time of flowering it is like the ovary 

 of lamarckiana, neither smaller nor larger. But it is only reached by 

 very few pollen-tubes, and is therefore always very incompletely 

 fertilized. It does not fall off after the fading away of the flower, as 

 unfertilized ovaries usually do; neither does it grow out, nor assume 

 the upright position of normal capsules. It is checked in its develop- 

 ment, and at the time of ripening it is nearly of the same length as in 

 the beginning. Many of them contain no good seeds at all; from 

 others I have succeeded in saving only a hundred seeds from thousands 

 of capsules. 



These seeds, if purely pollinated, and with the exclusion of the 

 visits of insects, reproduce the variety entirely and without any 

 reversion to the lamarckiana type. 



Correlated with the detailed structures is the form of the flower- 

 buds. They lack the high stigma placed above the anthers, which in 



