378 



GENETICS IN RELATION TO AGRICULTURE 



Since the true nature of Winkler's chimeras has been made clear a 

 number of historical cases of graft-hybrids have been investigated. The 

 results of this work have been summarized by Buder whose list appears 

 in Table LIII. Most of these cases have been fully discussed in other 

 works. Typical leaves of the two types of Crataegomespilus and of 

 the two parents, the whitethorn and the medlar, are illustrated in 

 Fig. 154. 



TABLE LIII. LIST OF THE MOST IMPORTANT PERICLINAL CHIMERAS PRODUCED 

 BY GRAFTING. (Adapted from Buder.) 



In addition to the above there are the Bizarria as they have been termed. These are periclinal 

 chimeras (some of them perhaps also sectorial chimeras) between different species of Citrus: Pomeranze, 

 Citrone, Cedrate, Limette. The earliest record of these dates from Florence, 1644. _ They aroused _in- 

 terest in their day because of the manifold sectorial and periclinal chimera combinations in their fruits. 

 Although most of these forms are now forgotten, several are still in cultivation, but they have not 

 received close study (but see COIT, "Citrus Fruits"). 



Baur's Investigation of a Natural Chimera. The key to the ex- 

 planation of Winkler's artificially produced chimeras was furnished by 

 Baur's discovery of the difference between the white-edged and solid 



