THE INHERITANCE OF DOUBLENESS IN MAT- 

 THIOLA AND PETUNIA. I. THE HYPOTHESES* 



HOWARD B. FROST 

 Citrus Experiment Station-. University of California 



The peculiar inheritance of "doubleness" in stocks 

 {Mai thiol a) lias long been a matter of special interest. 

 Some races produce only single-flowering" plants. A pure 

 double-flowering race, on the other hand, is an impossibil- 

 ity; the doubles are absolutely sterile, stamens and pistils 



being entirely absent. Certain races, however, consist of 

 both singles and doubles, in nearly equal numbers, 1 each 

 generation being descended from the singles of the pre- 



* Paper No. 17, Citrus Experiment Station, College of Agriculture, Univer- 



1 The usual proportion of doubles in large cultures ?eems to be near 53 

 per cent., or perhaps slightly higher in some eases. 



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