246 MUTATIONS OF OENOTHERA SUAVEOLENS DESF. 



(1) Oenothera suaveolens mut. apetala 



In visiting the different stations of the forest of Fontainebleau 

 in 1913 I observed a specimen with two or three flowers without 

 petals. They were its only open flowers, and no trace of a corolla 

 could be found. It bore some ripe capsules, but from the seeds of 

 these the anomaly has not been repeated, although more than one 

 hundred offspring have flowered and have been observed daily 

 during the two or three months of their blooming period. 



In 1916 an apetalous mutant arose among the offspring of one of 

 the self-fertilized individuals of mut. jaculatrix of the previous 

 year. It was distinguished by somewhat broader leaves through 

 the whole summer and began to flower in September. Soon after- 

 wards it flowered on twenty or more side branches, giving a pro- 

 fusion of flowers, among which almost daily some were without 

 petals. The majority of the flowers, however, had 1—4 petals, and 

 showed all intermediates between hardly broadened stamens and 

 the normal, oval form of the petals of Oe. jaculatrix. On specimens 

 with more than one petal these differences could sometimes be seen 

 in the same flower. Flowers with a normal corolla were rare; they 

 repeated the type of the parent. The apetalous flowers often open 

 only sideways, the sepals remaining united at their tips and covering 

 the self-fertilized stigma. 



On Sept. 20 I counted the petals of all the flowers of that day and 

 in the buds for the next day. I found 



Total 53 



There were thus 1 1 percent of apetalous flowers. This proportion 

 varies, however, on different days. This behavior is the same as in 

 my half races among other genera, as e.g., in Trifolium pratense 

 quinquefolium, which may be rich in leaves with 4—5 leaflets, with- 

 out ever losing those with 3. 



Since I have not as yet cultivated any offspring, the opinion 

 that this individual belonged to a half race is founded only on its 



