METHODS OF POLLINATION. 33 



anther-cells, which they actually penetrate, and so 

 get to the stigma, upon which the anthers are closely 

 applied. 



There are a great many other plants of various 

 families which possess these self-fertilizing buds, 

 termed Cleistogamous, a word meaning " concealed 

 union." Another common flower which is self- 

 fertilizing is that of Gassytha (Fig. 17), a plant which 

 is remarkable for its leafless, thread- 

 like stems, which are jparasitic upon 

 the bushes about which it entwines 

 itself in a tangle-like mass ; but I 

 shall have occasion to describe this 

 flower and the plant's peculiar habit 

 later on. 



It often happens that a flower 



^ ^ Fig. \1.—Cas'sytha. 



invites insects at first, then turns ^^''^'^^J^'lf '*'" ''^ 

 to self-pollination afterwards. Thus, 

 in many flowers when in bud, the anthers are all 

 turned inwards; but when the flower expands, the 

 filaments bend outwards ready to dust the insect 

 visitor as soon as it comes. Afterwards, the filaments 

 curl inwards again, and the pollen can drop upon the 

 stigmas of the pistil in the middle of the flower (see 

 Fig. 10 of the peach). 



One of the British Clovers, of which Fig. 18 is an 

 illustration, is a case in point. It is particularly 

 adapted to some wild " humble-bees " in England, and 



D 



