THE WORK OF FLOWERS 



303 



Where both anthers and seed - case are borne in the 

 same flower, self-poUination is often prevented by 

 having them active at different times ; thus the stigma 

 is pollinated and withers long before the anthers of the 

 same flower are open in Deutzia, Elm and Plantain 

 (this method is especially common in the Rose, Honey- 

 suckle, Nightshade and Mustard families), while, on 

 the other hand, the 

 anthers mature first 

 in a great variety 

 of flowers (espe- 

 cially common in 

 Pea, Mallow, Pink, 

 Mint and Composite 

 families) . This can 

 be clearly seen in 

 Fig. 166 (^), which 

 represents one of 

 the small flowers 

 from the center of 

 a head of the gar- 

 den Graillardia. The 

 flower is tubular 

 and is represented 

 as cut open so as 

 to show the anthers {an) , which are united together to 

 form a small tube into which the pollen falls and 

 so comes directly on the stigma {st) : nevertheless, self- 



B 



166. Gaillardia flower cut open, a, bud, showing the 

 pollen falling on the style (st); b, open flower, 

 showing the style-branches bent back ready to re- 

 ceive pollen from another flower. 



