278 



PLANT STRUCTURES 



tirely ; sometimes iliej become a tuft of delicate hairs, as 

 in Arnica (Fig. 261, D, E), thistle (Cnicus), and dandelion 

 (Taraxacum) (Fig. 263), surmounting the seed-like akene 

 and aiding in its transportation through the air ; sometimes 

 they are converted into two or more tooth-like and often 



Fig. 263. Flowers of dandelion, showing action of style in removing pollen from the 

 stamen tube: 1, style having elongated throngh the tube and carrying pollen; 2, 

 style branches beginning to recurve; 3, style branches completely recurved.— 

 From " Field, Forest, and Wayside Flowers." 



barbed processes arising from the akene, as in tickseed 

 {Coreopsis) and beggar-ticks (Fig. 188) or Spanish needles 

 (Bidens), to lay hold of passing animals ; sometimes they 

 become beautifully plumose bristles, as in the blazing star 

 (Liatris) ; sometimes they simply form a more or less con- 

 spicuous cup or set of scales crowning the akene. In all 

 of these modifications the calyx is called pappus. 



The stamens within the corolla are organized into a 

 tube by their coalescent anthers (Fig. 263), and discharge 

 their pollen within, which is carried to the surface of the 



