4 Bailey , Adventilious Vegetation ofSt.Atute's-on-the-Sea. 



Brunswick ; Steberburg, September, i88i. 



Leg. E. Krummel. 

 Spain ; Andalusia, Malaga, 29 August, 1889. 



Leg. E. Reverchon. 

 Tyrol ; Innsbruck, Holting, 29 September, 1883. 



Leg. J. Murr. 

 It has been found in Denmark, and also as a casual in 

 England either as a garden weed or with ballast. The 

 late date of its flowering is remarkable in all these 

 continental examples, and corresponds with what takes 

 place at St. Anne's. 



The genus Ambrosia forms a portion of a somewhat 

 aberrant group of the Composita:, by reason of its .species 

 possessing a superior ovary, by the absence of some 

 portions of their floral envelopes, and by the anthers not 

 being truly syngenesious as they are in the other groups 

 of that natural order ; hence some systematists form the 

 group into a separate natural order. It has a wide 

 distribution in both hemispheres ; the larger number of 

 species belong to North America, while the rest are found 

 in tropical Africa and India, as well as in the countries 

 who.se shores are washed by the Mediterranean. 



Auibrosia artemisuefolia is monoecious, both male and 

 female flowers being found upon the same plant ; but 

 in the St. Anne's plants a curious arrangement of the 

 flowers at one time led me to think that the plant was 

 dicEcious, because spikes bearing conspicuous male flowers 

 would be found growing by themselves, and other plants 

 bearing conspicuous female flowers grew by themselves ; 

 but a little examination disclosed the fact that the other 

 sex was present, though in much less proportion. The great 

 mass of the plants bore the male flowers in profusion on 

 the upper portion of the flowering spike, while the female 

 flowers were below in greatly reduced numbers. 



