254 



ANGIOSPERMAE — DICOTYLEDONES 



cushion'). When an insect pushes its head into the flower, the connective-plate 

 blocking the entrance is pressed upwards and backwards, so that the fertile anther- 

 lobes, covered with pollen below, are twisted forwards and downwards. 



Fig. 328. .Sd/i/ia /rd/tfwj/j, Z.. (after Herra. Miiller). (i) Flower seen from 



the right. (2) Stamens .seen from the right front ( x 2). a, 61aments : b and c, 



upper and lower limbs of the connectives; </, upper anther-lobes; *, lower do. 

 modified into a plate closing the entrance to the corolla-tube ; y^ point where the two 

 lower anther-lobes are united ; ^, style in the first stage; ^, do. in the second stage. 

 The dotted line b' d* indicates the position assumed by the anthers when twisted 

 down. 



In this way not only is the entrance to the nectar opened, but the fertile anther- 

 lobes are brought down on to the visitor's back, dusting it with pollen. When the 

 insect withdraws its head from the flower, the anthers resume their former position. 



mfm Iff ^^ ^ mf. ^^^, 



Fig. 329. Salvia pratensis^ L. falter Herm. Miiller). A. Large flower, after removal of part of the 

 corolla. B. Small do. (x 2). C Do., more strongly magniGed. D-K. Stamens in various stages 

 of reduction ( X 7). L. h stamen of .S". officinalis, L. a and a', upper and lower anther-lobes ; 



c, connectives ; ca, calyx ; yf, filaments ; gr, style ; «, nectary ; ov^ ovary ; st^ stigma. 



In older flowers the stigmatic surfaces are situated in the entrance, so that insects 

 brush against them first. They mature until the anthers have dehisced. Hermann 

 Miiller says, therefore, that automatic self-pollination is excluded. He observed small- 

 flowered female stocks in the Alps as well as the large-flowered hermaphrodite form, 

 the lever-mechanism in the former being reduced to a variable extent. The less 



