Fig. 172. — Two types of double flowees in Sweet William [Dianthus barbatus). 



One due to simple petalody of the stamens giving 15 petals; the other 

 with many more petals, since petalody is accompanied by splitting. 



Fig. 173. — Three grades of doubles in Hollyhock {Althaea rosea). 



ITo face p. 473. 



