22S THE STRUCTURE OF FLOWERS. 



Caltlia palustris is said to be androdioecious, but no 

 details are given by the observer.* 



Besides the JJmhellifera!,\ where andromonoecism seems 

 to be a characteristic feature, Miiller mentions Asperula 

 taurina and Galium Cruciata, Pidmonaria officinalis^ Coriaria 

 myrtifolia,ai\d Biospyrus Virginiana as being andromonoecious. 

 The hermaphrodite flowers of these species are protandrous. 



In Galium Cruciata^ Mr. Darwin noticed that the pistil is 

 suppressed in most of the lower flowers, the upper remaining 

 hermaphrodite. 



Heterostylism may tend to produce the same result when 

 the stamens of the long-styled forms degenerate so far as to 

 become atrophied without the pistil losing its functions. 

 Pidmonaria angustifolia and Phlox suhulata give hints of this 

 condition,;!: Asperida scoparia was at first thought by Mr. 

 Darwin to be heterostyled, but finding the anthers to be des- 

 titute of pollen, he considered it to be dioecious. A. taurina, as 

 figured by Mii]ler,§ shows great variability in the lengths of 

 the filaments and styles, and he pronounces it to be andro- 

 monoecious. Hence, as so many of the Euhiacece are hetero- 

 styled, there seems every probability of one result of this 

 peculiarity, being one or other kind of this incompletely 

 affected or partial diclinism. In the case of Coriaria myrti- 

 folia, Hildebrand found that it was the first flowers which 

 were male only. In Maples, as in Galium Cruciata, the rule is 

 for the three or more flowered corymb to have the central 

 one hermaphrodite, and the lower or outer ones male. This 



* Lecoq, Geog. Bot., torn, iv., p. 488. 



t Miiller says that in Sanicula Europcea the outer flowers are male, 

 and develop after the inner ones, which are hermaphrodite. This is so 

 anomalous, that one suspects an error somewhere. I have not hud any 

 opportunity of examining fresh flowers. 



X Forms of Flowers, p. 287. 



§ Fertilisation, etc., p. 303. 



