DEGENERACY OF FLOWERS. 



255 



dictum tliat, whether flowers were pendulous or erect, the 

 stigma was always below the anthers, so that pollen could 

 fall upon it — the anthers are always closely applied to the 

 stigmas, as may bo seen in Chickweed (Fig. 52), and small- 



Fig. 52. — Flower-bud, closnd and expanded, 

 of Stdlaria media, showing petals reduced 

 in size; stamens, three oulj^ anthers 

 closely adpresscd on stigmas. 



€b 1). 



Fig. 53. — Stamens and stigmas of 

 Epilohiuin monlanum, the bud 

 scarcely open, while anthers are 

 closely applied to the stigmas. 



flowered Willow Herbs (Fig. 53), and especially in cleistoga- 

 mous flowers (Figs. 56-59, pp. 258-261). 



The structure of the anthers and stigmas is often 

 greatly altered in form, besides being merely reduced in 

 size. 



As an illustration of the above remarks, the genus Viola 

 is interesting as furnishing two " forms " of the same species, 

 T^. tricolor, or Pansy, the one 

 being adapted to insects, the other 

 to self -fertilisation ; while other 

 species, such as V. odorata, the 

 Violet, bear cleistogamous buds 

 on the same plant as the ordinary 

 violet blossom. 



The dimorphic flowers of Viola 

 tricolor were first noticed by 

 Miiller, who described them as follows : * "In the large- 

 flowered form, the stigmatic cavity (Fig. 54, a, st) lies somc- 

 * Nature, Nov. 20, 1873, p. 45. 



Fig. 51. — Stylos and stigmas of the two 

 forms of I'ansy : a, tliat of the larger 

 and intercrossing; b, that of the self- 

 fertilising form. 



