248 



FLOWERS AXD THEIR WORK. 



Stinging-Nettles. Flowers small and green, male and female 

 either on separate plants or on the same plant. In the male flower 



STIGMA 



Fig. 89. Male and Female Flowers of Nettle. 



the stamens are at first folded inwards and downwards, but on warm, 

 dry days they spring up violently and scatter the pollen in a cloud ; 



Fig. 90. Male and Female Flowers of Dog's Mercury. 



cut off a branch bearing male flowers, and observe this on touching 

 the coiled-up stamens or warming the flowers. Female flower with a 

 tufted stigma (Fig. 89). 



Dog's Mercury. Flowers small, 

 green, dioecious ; stamens numerous ; two 

 large stigmas (Fig. 90). Some honey is 

 secreted, and the flowers are often visited 

 by small insects. 



Plantain. Flowers in a spike, mark- 

 edly protogynous ; when the stamens of the 

 lower (older) flowers hang out, after the 

 withering of the stigmas, the stamens of 

 the upper (younger) flowers are still in the 

 bottom of the corolla- tube, and the stigmas 

 projecting outwards and ready for pollina- 

 tion (Fig. 83). Some species have coloured 

 anthers, and are slightly scented ; these are 

 sometimes visited by insects for pollen. 



Other wind-pollinated flowers which you should examine are those of 

 Hop (Fig. 91), Sedges, Rushes, Docks, Sheep's Sorrel, Crowberry, 

 Walnut, Oriental Plane, Ash, Elm, Grasses. 



Fig. 91 



Hop. A, Female inflorescence ; 

 B, Female Flowers. 



