No. 547] GENETIC AL STUDIES ON OENOTHERA 391 



crossed this species with grandiflora, hut the hybrids were 

 very far from Lamar clciana chiefly since the hybrids had 

 narrow leaves and lacked the persistent rosettes asso- 

 ciated with the usual biennial habit of the latter plant. 

 The results show clearly that any form crossed with 

 grandiflora to produce Lama rckian a Wkv hybrids must be 

 one with large persistent rosettes such as are presented 

 by the northern types of biennis. 



4. Further Races of Oenothera grandiflora Ait. 



A type of (Enothera grandiflora appeared in my cul- 

 tures of 1910 (Davis, '11, p. 204), first noted because of 

 its rosette of green, much crinkled leaves. This strain, 

 grandiflora I, was further cultivated in 1911 but has 

 proved less favorable for my purposes than the strains 

 A, B, and D, chiefly for the reason that its leaves have a 

 pronounced petiole and the stems bear towards their tips 

 dense clusters of flowering side shoots. The strain 

 grandiflora 7 is a well-defined type very different from 

 the much more common forms of grandiflora and as 

 such is of interest. 



To add to the data on the composition of (Enothera 

 grandiflora as it grows wild (Davis, '11, pp. 202-205) a 

 culture of 169 plants from wild seed, collected by Tracy 

 at Dixie Landing, Alabama, in 1907, was brought to 

 maturity during the season of 1911. In this culture 42 

 plants proved to be (Enothera Tracyi referred to above, 

 9 plants were unmistakably of the strain grandiflora I, 

 and the remaining 118 plants were close to the strains 

 grandiflora A, B, and D, which it will be remembered are 

 so similar as to be essentially of one type. 



It seems clear from my cultures of wild seeds, a total 

 during the past four years of about 300 plants, that the 

 prevailing form of grandiflora is that represented by the 

 strains A, B, and B, previously described (Davis, '11, 

 pp. 205-207). There is a range of variation, chiefly in the 

 breadth of the leaves, and these strains (A, B, and D) are 



