228 THE STRUCTURE OF FLOWERS. 



Caltha palustris is said to be androdicecious, but no 

 details are given bj the observer.* 



Besides the UmhellifercB,] where andromonoecism seems 

 to be a characteristic feature, Muller mentions Asperula 

 taurina and Galium Cruciata, Pulmonaria officinalis, Coriaria 

 myrtifolia,{nid Biospyrus Virginiana as being andromonoecious. 

 The hermaplirodite 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. 

 Pulmonaria angustifolia and Phlox subulata give hints of this 

 condition. + Asperula 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 Pjihiacem are hetero- 

 styled, there seems every probability of one result of this 

 peculiarity, being one or other kind of this incompletely 

 aft'ected 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 Muller says that in Sanicula Europcsa 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 had any 

 opportunity of examining fresh flowers. 

 X Forms of Flowers, p. 287. 

 § Fertilisation, etc., p. 303. 



