1894]. NATL'KAl. SCIKNCES OF PHIJ.ADEI.PHIA. 59 



to the list is Dracocephalnm nutans, a European plant which has 

 many individuals with all the anthers sterile. The plants which bear 

 the highly polliniferous anthers are much larger and more showy 

 that what may be called the female flowering plants, a fact I have 

 noted in other dimorphic species. 



Some European works have noted a mixture of species, or marked 

 varieties, of this plant in a wild state. The dimorphic character is 

 the probable explanation. 



Apetalism in Sisymbrium Thaliana. 



Apetalism is not common in Crucifene. I have noted tendency in 

 this direction in Cakile and in Raphanus. Early in the present sea- 

 son 1893 the plant being a common weed in my garden, I found 

 apetalous flowers very common. Numerous instances of flowers with 

 only one, two or three petals, were also observed. Later in the season 

 there was seldom found any variation from the normal condition. 

 No difference in strength, position, or any other condition could be 

 observed that would satisfactorilv account for the abortion. 



