VEGETABLE CHIMERAS 



EGETABLE chimeras, known also as graft hybrids, are 



~ plants of a hybrid nature, which, however, have not 

 arisen through seed production, but as adventitious shoots 

 springing from the callus formed at the junction of stock and 

 cion in grafting. Two classes of chimeras are recognized, 

 sectorial and periclinal. In sectorial chimeras the tisues of the 

 two parents or members, stock and cion, are united side by 

 side in the growing point so that the parts of the chimera 

 resembling the respective parents may be separated longitudi- 

 nally. A periclinal chimera is one in which the center of the 

 plant consists of tissue of one parent overlaid by a layer of 

 tissue of the other plant from one to two or possibly more cells 

 in thickness. In the latter case, the individuals may often bear 

 the most striking resemblance to real hybrids, being complete 

 blends between the two parents in both vegetative and repro- 

 ductive parts. 



Chimeras have been known for about 270 years. Probably 

 the first on record was produced in Italy in 1644 between the 

 orange and citron the fruit resembling an orange with a section 

 of citron. Such fruits were called bizarrias because of their 

 peculiar appearance. In recent years, similar chimeras have 

 been reported as originating in Florida between the orange and 

 grape fruit. A very beautiful chimera of recent origin is that 

 of an apple produced by Prof. AA'. E. Castle of the Bussey 

 Institution by grafting a ''Boston stripe" upon the ''golden 

 russet". In this case, the stem end half of the apple is russet 

 while the blossom end is of the "Boston stripe". Among the 



