360 Origin and Behaviour of Oe.nothcra rubricalyx 



the fact that (jrandifiora frequently has dark rod stems while in Oe. 

 Lamarckiana and its derivatives (except rubricalyx) the stems have 

 very little diffuse red, though they are covered with red papillae. 

 I have not, however, found this " negative correlation " to be uni- 

 versal, since for example in some families the liybrid plants have 

 red buds and red stems as well. It is probable that the alternation 

 in Shull's hybrids is really between the dark red stems of some 

 grandiflora races and the green or nearly gi-een stems of forms in 

 the Lmnarckiana series. 



Finally, it must be made clear that ShuU's results, such as they are, 

 can only be used for reference if in every case, for ruhricalyx, we read 

 rnhricalyx x grandijiora. 



LITERATURE CITED. 



Gates, R. R. 1909. " An Analytical Key to some of the Segregates of Oenothera." 

 Ann. Rept Missouri Dot. Garden, Vol. xx. pj). 12.3 — 137. 



1910. "The Material Basis of Mendelian Phenomena." Amer. X(tt., Vol. 



XLIV. pp. 203—213. 



1911. "Studies on the Variahility and Heritability of Pigmentation in 



Oenothera." Zeitsckr. f. ind. Abst. u. Vera-b. Bd. iv. pp. 337 — 372, pi. 6, 5 figs. 



1912. " Mutation.s in Plants." Bot. Jour. Vol. II. pp. 84—87, fig. 1. 



1913. "A Contribution to a Knowledge of the Mutating Oenotheras." 



Trans. Linn. Soc. London, Botany/, Vol. vill. pp. 1 — 67, pis. 1 — 6. 



1914. "Breeding Experiments which show that HyliridiKition and Muta- 

 tion are Independent Phenomena." Zeitschr. f. ind. Abst. u. Vererh. Bd. xi. 

 pp. 209—279, 25 fig.s. 



Shhll, G. H. 1914. "A Peculiar Negative Correlation in Oenothera Hybrids." 

 Journal of Genetics, Vol. IV. pp. 83 — 102, pis. 5, 6. 



