68 



Elementary Work in Botany, 



petal with your pencil. Try the left petal, holding the 

 pencil horizontally in the channel on the upper side. Does 

 the style then push upwards through the apex of the pouch 

 formed by the lower petals ? Which side of the style is 

 hairy ? What do the hairs brush out of the pouch ? Try 

 to estimate the weight of an insect which resting on the 

 petal would cause the style to protrude. Is a honey bee 



heavy enough ? Where 

 would the pollen brush 

 rub against the insect? 

 Instead of pressing with 

 the pencil upon the left 

 petal only, let the point 

 pass obliquely across to 

 the right petal. Do yo.u 

 think an insect would be 

 likely to place some of 

 its feet over on the right 

 side ? Would that make 

 the style with its pollen- 

 brush work better? Is 

 the weight of the insect the only power which it can use to 

 bring the petals down ? Would an effort to push up the 

 base of the erect petal add to the downward push of his 

 weight ? Would such an effort help an insect to get at the 

 nectary ? Where is the nectary ? 



Look out for insects among the sweet-peas to-morrow 

 morning. Save your sweet-peas or bring more for the 



Fig. 51. A. Face of a sweet-pea, a a. Side or 

 wing petals, the one on the left higher and overlap- 

 ping the other at the apex. b. The upper or banner 

 petal, k. The lower pair of petals united, forming 

 the keel, which encloses the stamens and pistil. B. 

 Shows how a bumblebee mounting the wings on the 

 left side brings them and the keel down, thus 

 causing the style to brush pollen upon his right side 

 as with the petals he sinks to the level of the un- 

 yielding ovary. C. A magnified view of the style 

 as seen from the front, showing the brush of up- 

 turned hairs which sweeps the pollen out of the 

 pocket formed by the tip of the keel. s. The small 

 stigma. 



