Study of Sweet-peas. 67 



iting flowers in the first condition become dusted with 

 pollen which they rub off on stigmas of flowers in the 

 second condition. 



Kxamine the flowers in your bunch (umbel) of geraniums. 

 In what condition are the stigmas of the flowers just 

 opened ? * Examine a pistil in a flower which has shed its 

 petals and stamens. Note five projections at the base. 

 Examine still older pistils if you have them. A geranium 

 pistil is evidently made up of five parts. These parts are 

 carpellary leaves or carpels. Bring sweet-peas to-morrow. 



EXERCISE 37. 



Study of Sweet-peas. Hold the peduncle in a 

 natural position. Do the flowers face away from the plant 

 on which they grow ? How should they face to make them 

 most conspicuous ? Show how such a position would also 

 make them more convenient for the insects who are invited 

 to sip their nectar. Where do you think an insect would 

 alight? Observe that the upper petal is erect (or, as in 

 some forms, projects like a canopy over the others), and 

 that the side petals are nearly horizontal, covering the 

 lower pair, which are united and curve upwards. Which 

 of the side petals overlaps the other ? Hold a flower firmly 

 by the calyx and press downward upon the right-hand 



* Without a good lens it is not easy to tell when the anthers are shedding 

 pollen, but it is evident that at first the closed stigmas would not receive pollen, 

 for the outer surface is not stigmatic (naked and sticky). Double geraniums are 

 monstrosities and teach us nothing concerning fertilization. If possible, study 

 wild flowers, particularly those with irregular corollas. 



