80 



THE HARMONIES OF NATURE. 



of fructification in all the higher plants. Thus, both the corolla 

 and the calyx may be wanting, as for instance in the vast family 

 of the grasses, which spreads in thousands of species over the 

 face of the globe. 



The pistil or pistils for they vary in number from one to 

 twelve, and sometimes more commonly appear in the centre of 

 the corolla, from which they rise like so many green columns. A 

 pistil consists of three parts the stigma at its upper extremity, 

 which is sometimes globular, sometimes cleft, sometimes cross- 

 shaped ; the style or hollow pillar which supports the stigma ; 

 and the germen, or seed-bud, which forms its pedestal or base, 

 and in which the germs or ovula are contained. 



The stamens, which resemble threads, or pillars, usually stand 

 between the corolla and the pistil, but are extremely various in 

 their arrangement and number a circumstance on which 

 Linnaeus founded his method of classifying plants. Some have 

 but one stamen, others two, three, and so on up to ten, twelve, 

 twenty, or even several hundreds. In some flowers we find the 

 stamina standing apart from each other, in others united by 

 their filaments into one or several sets ; here they are all of 

 equal length, there of unequal dimensions ; sometimes they are 

 attached to the inside of the calyx, sometimes to the corolla, to 

 the receptacle, or to the pistil. They invariably consist of two 

 parts, the anther and the filament. The anther is the summit of 



the stamen, and contains 

 the mealy or powdery sub- 

 stance called pollen, which, 

 brought into contact with 

 the stigma, serves to fecun- 

 date the ovula contained 

 within the germ. When 

 come to maturity, the an- 

 thers open in various ways 

 longitudinally or trans- 

 versely, or through the 

 raising of a lid, or through 

 numerous apertures, so that 

 the pollen contained in its 

 interior becomes free and 

 covers its surface with a fine generally yellow-coloured powder. 



Pollen-Grams of 



a, althaea rosea ; b, cobaea scandens ; c 

 ccerulea ; d, ipomcea purpurea. 



