DEVELOPMENT OF PLANTS 



477 



«£3' 



Fig. 331. Fig. 332. 



Fig. 331. A common species of the Mint family: A, inflorescence of the 

 skullcap {Scutellaria). Note the square stem, opposite leaves. Why are 

 all the flowers facing one way? B, flower enlarged, showing the two-lobed 

 under lip and the three-lobed upper lip which conceals the sporophylls. C, 

 section of the flower. Ovary four-lobed, stamens cohering with the corolla 

 and anthers concealed with the stigma beneath upper lip. Purpose of the 

 crest, c, on the calyx? 



Fig. 332. Flower of the sage (Salvia): A, flower after the anthers have 

 shed their spores. The two-lobed stigma is bending down into the position 

 occupied by them. B, sectional view of the flower, showing four-lobed ovary 

 with nectar glands at the base; stigma not receptive and bent back. As the 

 insect enters the flower he pushes against the sterile lobe of the anther, t, and 

 thus causes the fertile lobe, a, to swing down upon his back. /, filament of 

 anther. 



