Monstrosities 419 



ference often indicates what may be expected 

 from further culture. Stray tricotyls point to 

 poor or half-races, while more frequent devia- 

 tions suggest rich or double-races. In both 

 cases however, the trial must be made, and this 

 requires the isolation of the aberrant individ- 

 uals and the determination of their hereditary 

 percentage. 



In some instances the degree of their in- 

 heritance is only a very small one. The iso- 

 lated tricotyls yield 1 or 2fo of inheritors, in some 

 cases even less, or upwards to 3 or 4^. If the 

 experiment is repeated, no amelioration is ob- 

 served, and this result remains the same during 

 a series of successive generations. In the case 

 of Polygonum Convolvulus, the black bindweed, 

 I have tried as many as six generations without 

 ever obtaining more than 3^. With other 

 species I have limited myself to four successive 

 years with the same negative result, as with 

 spinage, the Moldavian dragon-head {Dracoce- 

 phalum moldavicum), and two species of corn 

 catch-fly (Silene conica and 8. conoidea). 



Such poor races hardly afford a desirable ma- 

 terial for further inquiries. Happily the rich 

 races, though rare, may be discovered also from 

 time to time. They seem to be more common 

 among cultivated plants and horticultural as 

 well as agricultural species may be used. Henq) 



