1 9 1 7] DE VRIES— OENOTHERA 



9 



the time of the most abundant flowering, has induced me to choose 

 for this mutation the name of 0. spiralis. 



As to the other marks, they were probably all evolved under 

 the influence of the very narrow leaves, which could not produce 

 food enough for very stout individuals or organs. The leaves 

 measured 5-6 mm. in breadth by a length of 8-10 cm.; they were 

 smooth (without bubbles) as in the parent, not folded longitudi- 

 nally, only a little hairy, and dark green. The internodes were 

 % long, reaching 2 cm. or more, and the foliage was therefore thin and 



the whole habit slender. The flower buds were less hairy than in 

 0. blandina, but more so than in 0. Lamarckiana, and broader than 

 would be expected from the narrow petals. The stigma was above 

 the anthers, which contained a good supply of pollen, making 

 artificial self-pollination and crossing: quite easy. The fruits were 



thin 



more 



It should be pointed out that the origination in 4 specimens, 

 one from one parent and the 3 others together from another parent, 

 is analogous to the production of 0. blandina itself, which arose in 

 3 specimens from one lot of seeds. It points to an internal condi- 

 tion of heritable mutability and suggests the expectation that 

 under a better climate and with more suitable conditions of culti- 

 vation the number of simultaneous mutations in the same direction 

 might increase sensibly. 



Crosses of O. blandina with other species. — In order to 



give proof that 0. blandina is really the mutant velutina, I made 

 some crosses with such species as are known to split 0. Lamar ck- 

 iana and some of its other derivatives into the twin hybrids laeta 

 and velutina. It is obvious that with the loss of the active qualities 



must 



The 



must 



give 



In other words, the crosses with these species must be expected to 



must 



crosses 



0. Lamar ckiana . 



