THE AMERICAN BOTANIST 



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more famous chimeras or graft hybrids may be mentioned the 

 much discussed Cyfissiis Ad ami which originated near Paris 

 about 1826. This was said to have been produced as the result 

 of a graft between Cyfissns purpurea and the common laburnum 

 or golden chain {Cytissus lahurnum) . Another is the White- 

 thorn medlar (Cratacgo-Mespihis) which is said to have 

 originated near ]\Ietz, Germany, by grafting the white thorn 

 (Crataegus monogyna) upon the medlar (Mespilus Gennani- 

 cus). As the above mentioned species do not cross, the origin 

 of these wonderful and perplexing forms remained a matter of 

 speculation until a few years ago when Professor Hans \Mnk- 

 ler produced chimeras experimentally between the common 

 nightshade (Solatium nigrum) and the tomato {Solauum lyco- 

 persicuni) , Using the cleft method of union, AA^inkler grafted 

 shoots of the seedling tomato upon the stem of the nightshade. 

 As soon as the union had taken place, the cion was cut near 

 its base in such a way that the cut surface consisted partly of 

 nightshade and partly of tomato tissue. Of the adventitious 

 shoots arising, only those which sprang" from along the line of 

 the union of the two specifically distinct tissues were allowed 

 to grow. Among a large number of adventitious shoots, about 

 3,000 is all, several were found which gave the desired result : 

 .i e. they were apparently hybrid in character. Some resembled 

 more closely the nightshade, some the tomato, while still others 

 were intermediate in foliage, flowers, and fruit. A number of 

 these were planted as cuttings and were grown to flower and 

 fruition. A few set seeds while others developed fruit but no 

 seeds. The seeds of one of them which A\'inkler named 

 SoJanum fubingense and which more closely resembled the 

 nightshade, developed into true nightshades while those of 

 another, Solauum proteus more closely resembling the tomato 

 gave pure tomato plants. Although Winkler had produced 

 experimentally plants that were hybrid in appearance, inasmuch 

 as the two plants were wholly blended, yet it was clear that they 



