56 PLANT HYBRIDIZATION BEFORE MENDEL 



thus chinensis y^carthusianorum^ so that Kolreuter is apparently 

 in error in his citation. Of the cross Dianthus hortensis \ chinen- 

 sis, three plants were produced. Kolreuter states: 



"Throughout, there was, between all these plants and those of the 

 reverse cross, both in what pertained to the whole external structure, 

 as well as also in respect to their inner characteristics, no essential 

 difference to be found." (p. 209.) 



The reciprocal cross is reported, not in the third "Fortsetzung," 

 but as Experiment 40 in the second. In regard to a cross of Dian- 

 thus chinensis X ^- superbus, a carmine-red form with double 

 flowers, it is stated of the hybrids, twenty in number, that : 



"Throughout, these plants held in all details the mean between the 

 female and male, except that they had bloomed earlier and longer." 

 (p. 212.) 



Most of the hybrids were infertile as to their pollen, even when 

 abundantly close-pollinated. The egg-cells showed on the other 

 hand a limited amount of fertility, giving, when open-pollinated 

 from other species in the neighborhood, not seldom capsules with 

 generally two to four seeds, and when hand-pollinated from these, 

 six to eight seeds. So far as the doubling of the petals is con- 

 cerned, it may be assumed that the hybrids were on the whole 

 intermediate, since, as Kolreuter says: 



"One sees plainly that the female contribution in respect to this cir- 

 cumstance is of a like activity and character with the male." (p. 213.) 



Of a cross Dianthus hortensis X harhatus it is stated (p. 216), 



"it showed quite plainly, that it had taken an equal share from both 

 natures." 



From a cross between a double Dianthus chinensis and a native 

 wild species, D. armeria, Kolreuter obtained ten plants, of which 

 he says : 



"Among all these hybrids, there was not a single one with simple 

 flowers, but all either with double, even more strongly reduplicated, or 

 quite doubled very decorative flowers ; a circumstance which again places 

 out of all doubt the activity of the female in respect to this point." 

 (p. 222.) 



These hybrids were in the highest degree infertile as to the 

 egg-cells, although exposed throughout the summer to pollina- 

 tion from various other natural species in the neighborhood, and 

 even when pollinated most carefully by hand, with pollen from 

 the male or the female parent or from other pinks, setting not a 



