PLANT HYBRIDIZATION BEFORE MENDEL 53 



hours, and he got as perfect seed-capsules and seeds as if he had 

 pollinated with the plant's own pollen. 



Inasmuch as Kolreuter reports this type of pollen also as being 

 present in Saponaria officinalis and in Gypsophila fastigiata, it 

 seems probable that he was dealing with a pathological condition, 

 due possibly to a fungus infection. At jill events he reports that 

 the shedding of this pollen took place at the same time and in 

 the same manner as in these plants generally. It is interesting to 

 note his comparison of the abnormal pollen grains in question, in 

 respect to color, form and size with the smut of oats, and of other 

 grains. The second "Fortsetzung" closes with brief accounts of 

 crosses of Hibiscus manvhot with H. vitifolius and its reciprocal ; 

 Datura stramonium with D. taiula and its reciprocal ; Mirabilis 

 jalapa red-flowered X yellow-flowered and reciprocal ; and Leu- 

 cojum red-flowered X a white-flowered variety. 



With respect to the Hibiscus cross, it is only of interest to note 

 the intermediac}^ of the four plants from each cross and their com- 

 plete resemblance to one another. In the Datura cross between 

 stramonium with white flowers, and tatula with violet flowers, the 

 hybrids from the two reciprocals, five and thre'e, respectively, 

 were completely alike. The purple color did not dominate. Kol- 

 reuter says : 



"Their flowers had a whitish color playing a little into the violet; 

 the flower-tubes marked with five violet stripes, and the others sky- 

 blue." (p. 161.) 



In the Mirabilis reciprocals, the color 



"in the case of both the hybrid varieties was of mixed red and yellow. 

 The flowers played into orange-yellow." (p. 161.) 



In the Leucojum red X white cross, the six hybrid plants all 

 had whitish-violet flowers. 



Kolreuter's "Dritte Fortsetzung" is dated from Karlsruhe, 

 December 26, 1765. The memoir opens with a brief statement to 

 the effect that, after his success in 1762 at Sulz on the Neckar, 

 in the production of various hybrid plants, he had experienced 

 still greater success in 1763 at Calw, in obtaining, in addition 

 to fertile crosses with four species of Verbascum, several other 

 fertile combinations in the same genus, involving chiefly the re- 

 ciprocal crossing of the species native to the locality. The seeds 

 from these crosses were grown at Karlsruhe in 1764, and came 



