230 



THE STUDY OF FLOWERS. 



receive some of this and thus cross pollination is effected. 

 See Fig. 95. 



Another well-known example is that of the violets or 

 pansies. Take, for example, a flower of the Heart's-ease 

 (Viola tricolor). Let pupils suggest the significance of 

 the "spur" upon the anterior petal. This should be 

 opened and the nectar-producing appendages of the two 

 anterior stamens observed. 



ANTHER 



POST. LOBE 

 -STIGMA 



LATERAL LOBE 



ANT, LOBE 



COROLLA 



OVARY ' 



~-RING OF HAIRS 

 f " CALYX 

 NECTARY 



Fig. 97. Flower of White Dead-nettle (Lamium album] in section. 



Stamens are mature before stigma. Nectary is protected by ring of hairs 



from small insects. Humble-bees pollinate. 



The position and form of the stigma should next be 

 noted. The end of the style is globular and has the stigma 

 in a depression on the anterior face, whilst it bears a pro- 

 jecting " shutter" beneath. The stamens are lower down 

 within the flower. As the insect pushes its head inward 

 it rubs on to the stigma any pollen it may be carrying, 

 whilst as it withdraws its proboscis the " shutter " protects 

 the stigma from receiving pollen from the same flower. 



