196 PLANT HYBRIDIZATION BEFORE MENDEL 



words, less than one year before the question as to the reason for 

 the preponderance of one parental contribution over the other, 

 was siated by Nageli as lacking facts for its elucidation, Mendel 

 had already presented the facts explaining dominance, 



Nageli, from the then generally existing point of view, stated 

 the mode of transfer of the characters in hybrids as follows : 



"The characters of the parental forms are, as a rule, so carried over 

 to the hybrid that, in every individual one, the mutual influence makes 

 itself felt. One character does not go over as it were unchanged from 

 one, the other unchanged from the other parental form, but there occurs 

 an inter-penetration of the paternal and the maternal character, and an 

 intimacy between their characters." (4c, p. 222.) 



Here again we have a statement which has been modified by 

 Mendel's discovery of dominance in variety-crosses. Nageli re- 

 marks, however, that those who have largely or exclusively 

 crossed varieties, or in crosses have given their attention to 

 "varietal characters" so-called, are of the opinion that the char- 

 acters go over unchanged, quoting the results of Sageret's ex- 

 periments referred to in a previous article. Despite these cases of 

 what is now known as dominance, Nageli states the general rule 

 as he saw it, thus : 



"The rule, however, is that the characters of the father and the mother 

 combine and interpenetrate, w^hereby a new individual character origi- 

 nates which holds more or less the mean. The way and manner in which 

 the union occurs cannot be determined in advance." {ib., p. 224.) 



Regarding the vigor of first-generation hybrids, Nageli remarks 

 as follows : 



"Growth and development of the individual is especially aroused in 

 species-hybrids. These are frequently larger than their two parents. They 

 form more and larger leaves, the stem is raised higher, and branches 

 more vigorously, and effects multiplication more easily through stolons, 

 rhizomes, etc. . . . Hybrids are also distinguished through the fact that 

 they bloom longer and more abundantly than the two parent forms. 

 The hybrid of plants which bloom first in the second year, blooms for 

 the most part in the first; the hybrid of plants which only come to 

 flower formation after a series of years, arrives thereat a few years 

 earlier. Likewise, with regard to the individual vegetative period, the 

 rule holds good that the hybrids begin to bloom earlier in the year and 

 continue to bloom later in the fall. In general, they often form quite a 

 large quantity of flowers, which are especially larger, sometimes also 

 more fragrant and intensely colored, and of which each individual one 

 lasts longer, for example several days ; when the flowers of the parent 

 species wilt after the first day." {ib., p. 228.) 



This closes the account of Nageli's contribution to the literature 



