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University of California Puhlications in Botany [Vol. 5 



original seed was received from the United States Department 

 of Agriculture. The parental types have been grown in the 

 University of California Botanical Garden (U. C. B. G.) for 

 five and seven years respectively under the direction of Pro- 

 fessor W. A. Setchell and have almost from the first been propa- 

 gated, in both cases, from "pure" seed in the pure line. The 

 principal and most striking characteristics which distinguish the 

 two types and the F^ hybrid are summarized in the following 

 table : 



It can be seen from the above table that, in general, one 

 would be justified, on the Mendelian basis, in considering the 

 N. Tahacum var. macrophylla parent as dominant and the N. 

 Tahacum var. virginica parent as recessive. After a general 

 examination in the field of the F^ generation, this dominance 

 would have been rather striking and, for convenience of refer- 

 ence and later discussion, the fact that such dominance was 

 apparent will be recognized. The fact that on close examination 

 of the hybrids the influence of the virginica parent was shown 

 in the leaf-shape and auricle, the flower-color and corolla lobes 

 and that, among the fifty individuals grown, the height of the 

 central axis was found to vary between 62 and 170 cm., the 

 width of the broadest leaf from corresponding regions between 

 15 and 37 cm., while the length of the longest leaf varied be- 

 tween 28 and 59 cm., all these, in general, support the con- 

 clusion arrived at in the following communication (cf. p. 117). 



