96 Self- Incompatibility in Hermaphrodite Plants 



single anther sac was observed to dehisce, and repeated examinations of 

 the contents showed that at least 95 "j^ of the pollen was shrivelled and 

 empty. On three other plants, a few anthers were observed to dehisce 

 partially, but in these the pollen was likewise largely impotent. All 

 these plants produced corollas that opened normally, and every one 

 produced large capsules with seed to free open cross-pollination. These 

 plants exhibited a one-sided impotence identical with that observed 

 in various species, such as in certain so-called self-sterile varieties of 

 cultivated grapes and of the navel orange. 



Twelve plants were fully potent both as males and females. They 

 bloomed from 16 to 28 days, and controlled self-pollinations were made 

 for from 20 to 64 flowers per plant. Five were completely self-incom- 

 patible, two were partially self-fertile, and five were highly self-compatible. 

 The latter gave fine large pods in nearly every flower from the first to 

 the very last to bloom. Of the partially self-compatible plants, one 

 produced pods only on first two dates of selfing, and the others produced 

 numerous but small pods indiscriminately throughout the period of 

 bloom. 



Summary. There was no evidence of " end-season " self-fertility in 

 any of these plants. Plants were strongly or feebly self-fertile from the 

 first flower that opened, and all plants completely self-incompatible 

 during the first part of the blooming period remained thus to the end. 

 In some cases of feeble self-fertility the self-fertility appeared to be 

 confined to the early and mid-season period of bloom. 



Eschscholtzia californica. 



For the seed of this species the writer is indebted to Professor 

 W. T. Home, who collected it from individual plants growing wild on or 

 near the campus of the University of California. Seeds of each of 

 5 plants were sown separately during March, 1918. All but three of 

 the plants were grown in pots in a greenhouse. Flowers were enclosed 

 in glassine bags and allowed to make autonomous self-pollination, a 

 procedure that supplies an abundance of pollen to stigmas at a time 

 when they are receptive to compatible cross-pollinations. The dehiscence 

 of the stamens of individual flowers continues for several days, during 

 which time the stigmatic branches of the pistil elongate, coil about 

 among the stamens and become covered with pollen. Pollen and 

 stigmas in this stage used in crossing most often give a rapid develop- 

 ment of fruit and seeds. 



