AUTOGAMY BY THE BENDING BACK OF STYLK-1U1 AN< 'HI -:s 



3G3 



of pollen by stigmas from the edge of the anther-tube I observed in several Com- 

 posites, as, for instance, in the species of the genera Adenostyles and Cacalia, and 

 in Arnica montana. The external surface of the style in Adenostyles is beset with 

 papillse, which give it the rough glandular appearance whence it derives its name of 

 Adenostyles ( = glandular style) ; it has no collecting-hairs, and the pollen is therefore 

 not swept but squeezed out of the anther-tube. The edge of the tube is furnished 

 with prongs, each of which is slightly revolute and is concave almost to the extent 

 of being boat-shaped, so that it is able to retain some of the extruded pollen. 'I'll is 

 pollen is only used for autogamy in the event of the stigmas not being dusted in 

 any other way. In that case the two style-branches roll back until the recepti\ 



Fig. 303. -Autogamy effected by means of an inflection of the style-branches. 



sssisislsssssassssss*- 1 ' 



tissue comes into contact with the edge of the anther-tube. The 

 Arnica montana (see figs. 303 > " ' ) have collecting-hau-s on the surface 

 ^rlghS-thicled Ips only, and in this case the pollen is 

 (figs. 303 > and 303*). A small quantity of the pollen . always 

 h! 5 toothed edge of the anther-tuhe. The manner an wh,ch the pollen u 

 fted to the Astigmatic tissue by means of the re-volution of the style-arms . shown 



we 



of on of pollen from the hai ; of the 



its inner surface. In the bud thh.rs are d^hon ^ y^ ^ 



n the Bell - flowere already 



