214 



BOTANY FOR BEGINNERS 



CHAP. 



pencil ; and when the next flower is visited, they come in contact 

 with the stigma and pollinate it. 



4 Flowers Pollinated by the Humble-Bee. Flowers like the 

 Clover, Vetch, and Pea are pollinated by the humble-bee, which 

 possesses a longer proboscis than most insects. In flowers of 

 this description the honey is stored deep down the tube formed 

 by the diadelphous (p. 185) stamens. 



EXPT. 1 88. Obtain a few inflorescences of the Clover and examine 

 them. Note 



(i) The inflorescence is a head of numerous flowers, 

 (ii) Each flower is zygomorphic (p. 179). 

 (iii) The calyx is gamosepalous (p. 183). 



(iv) The corolla is polypetalous (p. 183), and consists of a standard, 

 wings, and a keel. 



(v) The stamens are diadelphous 

 (p. 185), and ten in number. 



(vi) The pistil is monacarpous 

 (p. 186). 



(vii) The free stamen and small 

 opening down which the humble-bee 

 can pass its proboscis. 



(viii) If the standard is pressed 

 downwards, the stamens move so as to 

 discharge their pollen in a certain way. 

 (ix) There is only one way in which 

 honey can be extracted from the nectary 

 at the base of the tube formed by the 

 stamens. 



Cross-pollination by the 

 Wind. A large number of plants 

 are pollinated by the wind. They 

 include the great class of Grasses, 

 the -Hazel, Yew, Oak, and Plantain. 

 The chief characteristics of wind- 

 pollinated flowers are as follows : 



1. The flowers are small, simple, 

 and inconspicuous, thus presenting 

 a great difference to the brightly- 

 coloured insect-pollinated flowers. 



2. The flowers have no scent 



and do not secrete honey ; in fact, they have none of the 

 characters by which the entomophilous flowers attract insects. 



FIG. 212. Inflorescence of Plan- 

 tain, with protogynous flowers. 

 The upper flowers are closed, and 

 the styles hang out ; the lower 

 flowers have lost their styles, and 

 the stamens hang out. (S.) 



