322 



HUTCHINSON'S POPULAR BOTANY 



and usually number many thousands. They are the indus- 

 trious members of the community, who provide the food and 

 collect and give form to the raw material out of which the 

 cells are constructed. Secondly, there are the males or 

 drones, a less numerous company, though often amounting to 

 several hundreds ; and lastly there is the solitary female 

 or queen-bee, upon whose fertility the perpetuation of the 

 species depends. 



So it is with the plant. The foliage' leaves, which con- 

 vert the raw food materials derived from the root, etc., into 

 organic compounds, are the workers ; the stamens, with their 

 little sacs of meal-like pollen, answer to the males or drones ; 

 and the pistil, with its ovules, corresponds fairly well with 

 the female or queen. When it is added that the pollen of 

 the male organ is the fertilizing agent of the female organ 

 the means by which the ovules are converted into matured 



tand perfect seeds it will be seen how close is the analogy. 

 It may be asked, In what way does the pollen of the 

 male organ act upon the female organ ? The process may be 

 understood by reference to a section of the pistil of a well- 

 known flower, the Snapdragon (Antirrhinum majus, fig. 390). 

 Though differing very considerably in form from the pistil of 

 the Buttercup which we were looking at a few moments 

 ago, it resembles, in its main features, the individual car- 

 pels of that flower indeed, like the carpels, it consists of an 

 ovary (a), style (6), and stigma (c). The tiny round bodies 

 shown on the surface of the stigma are grains of pollen, which 

 have been conveyed thither from the anther-cells of the 

 stamens of another flower by insect agency, and it is by means of those 

 microscopic grains of yellow dust that the tiny unripe ovules in the swollen 



base of the pistil are to be fertilized, 

 and thereby made capable of growing 

 into perfect plant-producing seeds. 

 This is effected in the following man- 

 ner : On reaching the stigma, the 

 pollen-grains, stimulated by a viscid 

 secretion exuded from the stigmatic 

 surface, presently put forth tubes, which 

 force their way down the loose con- 

 ducting tissue of the style (fig. 396) 

 into the ovary, and so pass on to the 



FIG. 391.-BUTTEBOUP. OVule8 > Where i the , definite aCt f lm - 



Section showing receptacle (r) to which the carpels pregnatlOn takes place. 



(cp) are attached. They form collectively the pistil, T , . , 



and, when ripe, the fruit. ' It is important to get a clear grasp 



FIG. 390. 

 SECTION 



THROUGH 



PISTIL OF 



SNAPDRAGON. 



Ovary (a) ; style 

 (b) ; 'stigma (c). 



