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THE AMERICAN NATURALIST 



[Vol. XLV 



a blend of the parents, as he states ('11, p. 213), then 

 they can not be the same as the flower characters of 0. 

 Lamarckiana. If, on the other hand, the flowers are as 

 he states, " scarcely distinguishable from those of 0. La- 

 marckiana," then they are not a blend of the parental 

 characters. 



I have previously pointed out the differences between 

 0. grandiflora and 0. Lamarckiana (Gates. '99a, pp. 

 131, 132) and Miss Vail (in MacDougal, Vail and Shull, 

 '07, p. 66) has described the characters of 0. grandi- 

 flora in detail. For convenience, the flower differences 

 between 0. biennis, 0. grandiflora and 0. Lamarckiana 

 may he summarized here. 0. biennis has small flowers, 

 in which the stamens surround the stigma in the bud. 

 The anthers are in contact with the stigma in the bud 

 and are ruptured before the bud opens, so that when the 

 opening of the flower occurs, and the anthers move away 

 from the stigma, viscous strings of pollen are found 

 running from each anther to a lobe of the stigma in the 

 newly opened flower. Self-pollination thus invariably 

 takes place in 0. biennis. In neither 0. Lamarckiana 

 nor 0. grandiflora does this happen, for the reason that 

 the style is longer so that the stigma lobes, instead of 

 being surrounded by the anthers, are projected above 

 them. The anthers are ruptured as early as in 0. biennis, 

 but not being in contact with the stigma lobes, the 

 strings of pollen seen in the opening biennis flower never 

 occur in 0. Lamarckiana or 0. grandiflora. Tf, as Davis 

 states (see I. c, p. 216), the anthers in 0. Lamarckiana 

 touch the lower part of the stigma lobes, then these 

 strings of pollen and self-pollination would occur. But 



As regards the size of the flower, the statements of 

 Davis also need some revision. He assumes that the 

 flower of 0. Lamarckiana is smaller than that of 0. 

 grandiflora, whereas the 0. Lamarckiana of my cultures 



this conditio 

 it does oeeui 

 biennis X 0. 



