384 



AUTOGAMY. 



the crumbly pollen as it falls from them. Even if the pollen does not fall upon the 

 stigma autogamy does not fail; for the corolla slips along the style as it drops, and 

 is certain to touch both anthers and stigma, and to transfer to the latter the last 

 grains of pollen adhering to the anthers (see fig. 309 -). 



Reference has often been made in former chapters to the splendid creeper named 

 Gobcea scandens, one of the Polemoniacese native in tropical America, but capable of 

 thriving luxuriantly in the gardens of Central and Southern Europe, where it is 

 used for clothing espaliers, which it covers in the height of summer with deep- 

 purple bell-shaped flowers (see fig. 310 ^). The anthers are borne on long filaments 

 with hairy bases, and are situated, at the commencement of the flowering-period, 



Fig. 309.— Autogamy ensuing in consequence of the inflection of tlie pedicel and the disarticulntion of ttte corolla: 



Phygeliits capensis. 



I Portion of an inflorescence ; the flowers borne by a horizontal branch of the inflorescence in the successive stages of develop- 

 ment leading to autogamy (from right to left). 2 A single flower at the moment of the detachment of the corolla and the 

 rubbing of the anthers against the stigma. 



right in the mouth of the flower, where they are certain to be touched by insects 

 which enter the flower to get the honey. The style is still short at this stage, and 

 has its free extremity concealed under the anthers, whilst the three terminal 

 branches of the style which bear the stigmatic tissue are closed tightly together (see 

 fig. 310 ^). A little later anthers and stigmas change places; the filaments elongate 

 and twist themselves into the form of corkscrews, and the anthers then rest lower 

 than the three style-arms, which diverge and place themselves in a position to 

 receive pollen brought by insects from younger flowers (see fig. 310 ^). If no insects 

 make their appearance, and there is consequently no cross-fertilization, the pedicel 

 undergoes inflection to the extent of about 45°, and the flower, hitherto nodding, 

 becomes completely pendent. At the same time the style curves, and the coils of 

 the stamen-filaments are drawn closer together. The result of all these move- 



o 



ments is that the anthers are brought into contact with the stigmatic tissue, which 

 is still receptive, and autogamy ensues (see fig. 310 *). 



