402 



HUTCHINSON'S POPULAR BOTANY 



FIG. 497. FLOWER OF PEA (Pisum sativum). 



FIG. 498. SECTION OF PEA FLOWER 



after removal of calyx, wings, and standard, and one of the 

 petals of keel. In the remaining petal are the stamens and 

 pistil, and, in the conical cavity above the anthers, the pollen. 



FIG. 499. SECTION OF PEA FLOWER 



depressed in the direction of t'.ie arrow. When such de- 

 pression is ciused by the weight of a bee, the pollen-covered 

 style-brush is forced out and strikes against the underside of 

 the bee. 



of the power of smell in insects, 

 Kerner relates that when, some 

 years ago, the Aroid Dracunculus 

 creticus from Cyprus was planted 

 in the Vienna Botanic Gardens, 

 though there were no carrion-flies 

 in. the vicinity, nor refuse matter 

 of any kind to attract them, the 

 large foatid-smelling flower-sheath 

 no sooner opened than it was 

 freely visited by those insects, who 

 came flying thither from every 

 quarter. A captive Hawk-moth 

 which the same distinguished 

 naturalist let loose in the gardens 

 at a distance of two hundred yards 

 from a plant of Honeysuckle, flew 

 directly, straight as an arrow, to 

 the plant, and was found by Kerner, 

 who had placed a cinnabar-red 

 mark on the moth, hovering about 

 over the flowers. Here again scent 

 alone can have guided the insect. 



Perhaps it will now be said, If 

 scent and colour are the two chief 

 means by which insects are attracted 

 to flowers from a distance, what is 

 to detain and reward them when 

 the flowers are reached ? In other 

 words, What provision is made for 

 their reception ? This question is 

 answered by completing the list of 

 floral attractions which we have 

 named. Two out of the six have 

 been already dealt with. The re- 

 maining four are : Irregularity, 

 Honey-guides, Nectar, and Pollen. 



Irregularity is specially con- 

 nected with the comfort of the 

 insect. Labiate flowers, for ex- 

 ample, provide a landing-stage for 

 their visitors, as was pointed out 

 in the case of the White Dead- 

 nettle. The Calceolarias, which 



