282 



Retrograde Varieties 



cornuta) the sea-shore aster (Aster TripoUum), 

 corn-rose (Agrostemma Githago), the Sweet 

 William (Silene Armeria), and many garden 

 flowers, as for instance, the Clarkia pulchella, 

 the Polemofiium coerulemn, the Veronica longi- 

 folia, the gloxinias and others. If the red hue 

 is combined with a yellow ground-color in the 

 species, the variety will be yellow and the hy- 

 brid will have the red and yellow mixture of the 

 species as for instance, in the genus Geum. The 

 toad-flax has an orange-colored palate, and a 

 variety occurs in which the palate is of the same 

 yellow tinge as the remaining parts of the 

 corolla. The hybrid between them is in all re- 

 spects like the parent-species. 



Other instances could be given. In berries 

 the same rule prevails. The black nightshade 

 has a variety with yellow berries, and the black 

 color returns in the hybrid. Even the foliage of 

 some garden-plants may afford instances, as for 

 instance, the purplish amaranth (Amaranthus 

 caudatus) . It has a green variety, but the hy- 

 brid between the two has the red foliage of the 

 species. 



Special marks in leaves and in flowers follow 

 the same rule. Some varieties of the opium- 

 poppy have large black patches at the basal end 

 of the petals, while in others this pattern is en- 

 tirely white. In crossing two such varieties, 



