174 PLANT-LIFE 



greater advantage. In Fig. 58, s points to the stamens, 

 the stalk of each being known as the "filament," 

 which bears at its top a two-lobed anther; it is within 

 the anther that the pollen grains are formed. In 

 the same figure b points to the stigma, which is borne 

 on the style of the pistil; the style, in our subject, is 

 very short. It connects the forked stigma with the 

 ovary, wherein the ovules are formed. If we dissect 

 an ovary, we find that it is in two compartments, divided 

 lengthwise by a septum. This dividing membrane marks 

 the limits of two special floral leaves from which the 

 pistil is formed; they are called "carpels" (Gr. kwpos, 

 fruit). Honey-glands, or nectaries (Fig. 58, g), occur 

 at the bases of the shorter stamens. The Wallflower is 

 dependent to a large extent upon the visits of insects 

 in the business of pollination. Insects are attracted 

 to its service by the flaring advertisement of the showy 

 petals ; the nectar, which acts as a special lure ; and also 

 probably by the pleasant scent of the flower. Pollen 

 grains must be lodged on the stigma of the pistil, and 

 it seems desirable that the pollen formed by one flower 

 should reach the stigma of a different flower. This 

 involves cross-fertilization, which is thought to be a 

 benefit to the species. A bee visiting a flower thrusts 

 its proboscis down to the nectaries, and in doing so gets 

 its head dusted with pollen; when it transfers its atten- 

 tions to another flower it carries pollen to it, and some 

 of it is sure to come in contact with the stigma. The 

 stigma, when ripe, secretes a somewhat sticky fluid, in 

 which sugar is present. This fluid serves two purposes 

 — it causes the pollen to adhere to the stigma, and also 

 enables the grains to germinate. All Flowering plants 



