SENSITIVENESS AND IRRITABILITY OF PLANT ORGANS. 159 



cession, either towards the pistil as in the latter, or away 

 from it as in the former. Other flowers, like Cratcegus, liubus, 

 and Alisma, have them at first spreading away from, but 

 afterwards bending over the pistil. These processes facilitate 

 one or other kind of fertilisation, and are very common. 



Slow movements of the filaments after the anthers have 

 discharged their pollen, so as to place them out of the way 

 of the pistil, are not at all uncommon in strongly protan- 

 drous flowers. Echium* and Teucrium Sc-orodoniaf will illus- 

 trate this well-known phenomenon. The "lemon-scented" 

 or " oak-leaved " species of Pelargonium has small and very 

 irregular flowers, somewhat papilionaceous in appearance, 

 with the stamens declinate, lying on the anterior petal ; the 

 style lies beneath them, with the five stigmas quite undeve- 

 loped. After the anthers have shed their pollen, they fall 

 off, and the filaments bend down outside the flower, while 

 the stigmas now come to maturity and lie in the very place 

 where the anthers lay before them. 



Similar slow movements are very common in the styles 

 and stigmas of plants. In the CompositcB and Campanula, 

 Lobelia, Gentiana, etc., the style arms with their stigmatic 

 papillae curl backwards, and so secure self-fertilisation. 

 In several of the Scrophularinece and Lahiattv, the style 

 gradually bends ov^er, so that the stigma comes in contact 

 Avith the pollen. This, however, may be partly due to pro- 

 longed growth. As examples, may be mentioned Bhinanthus, 

 Melampyrum, Galeopsis, Stachys sylvatica, etc. Treviranus 

 says the same thing occurs with Gladiolus, the style curving 

 back towards the anthers. J 



* Cf. Figs. 20, h and c, p. 82 : h shows the position of the stamens 

 before pollination ; c, after it. 



+ See Miiller's Fertilisation, etc., p. 500, fig. 1G9. 

 X Ibid., p. 548. 



