STUDY OF A FAMILIAR PLANT 9 



12. A Staminate Flower (Fig. 4, S). This looks much 

 like the pistillate flower, and like it has sepals and petals. 

 But within the petals, instead of a pistil are three stamens, 

 which are attached near the base of the petals. Each stamen 

 has a short stalk or filament, and a larger head or anther. 

 Growing out from the upper end of each anther is a forked 

 leaf -like projection. When the anthers are ripe, they open 

 by long, curved slits and allow the dust-like pollen to escape. 

 This pollen is made up of small round grains. Some of the 

 pollen grains must fall upon the stigma of a pistillate flower 

 if seeds are to be formed. 1 The history of the germination 

 of the pollen grain on the stigma and of the growth of the 

 pollen tube from the pollen grain is a difficult one to follow 

 and will be taken up more fully in a later chapter. At the 

 center of the staminate flower is a whitish, three-lobed swell- 



' ing that looks like a- small stigma. This really is a rudimen- 

 tary pistil, which is quite useless in the 

 staminate flower. In the same way, the 

 pistillate flower has a circle of rudimentary 

 stamens, which are very small and easily 

 overlooked. 



13. The Fruit (Fig. 5). The fruit of 

 the cucumber is the part of the plant that 

 is of use to us, and so it is with the fruit 



that we are likely to be most familiar. It JT IG 5- Portion 

 is developed from the ovary of the pistillate of a cucumber fruit, 

 flower. As this part of the flower grows 

 rapidly, the other parts (sepals and petals, 

 style and stigma) wither away and may be seen for some time 

 as little dried-up structures at the outer end of the fruit. 

 Ordinarily the fruit is picked for use while it is still green. 

 But if it is allowed to remain on the vines it becomes yellow 



As a rule, plants will not form seeds or fruits unless pollen grains land upon 

 their stigmas. Cucumbers of some varieties are exceptions to this rule, for they 

 may form fruits (but fruits without seeds) though their stigmas receive no pollen. 



