294 THE LIFE OF THE PLANT 



existence of transitional forms and of so-called mon- 

 strosities, i.e. direct transformations. Let us dwell 

 upon some examples. 



When we were discussing flowers we had an oppor- 

 tunity of studying the sage, a plant used by chemists, and 

 remarkable for its adaptations for cross-fertilisation by 

 means of insects. We will try to demonstrate the existence 

 of gradual stages in the formation of this most interesting 

 flower from an apparently quite different flower, regular 

 and radially symmetrical in form. The sage belongs to 

 the family of Labiate flowers, so called on account of 

 their corolla having in most cases two lips. The wild 

 thyme, mint and other plants also belong to this class. 

 Botanists agree that the Boragineae are in many respects 

 very much like the Labiateae. We may take the forget- 

 me-not as a representative of the Boragineae. Everybody 

 knows that the blue corolla of this flower forms at its 

 base a short tube, and spreads out at the top, dividing 

 into five equal rounded lobes. If we peep into the 

 inside of the tube we notice five similar yellow anthers, 

 with their filaments attached to the tube (fig. 80).^ 

 Can we admit that the two-lipped flower of the sage 

 with its two peculiar stamens could have descended 

 from this regular star-like flower of forget-me-not with 

 its five stamens ? If we succeed in demonstrating in 

 other representatives of the same two families a series 

 of intermediate forms between the extreme cases we 

 have selected, we shall make this supposition most 

 probable. To begin with, we must point out the fact 

 that among the class of Boragineae, all the flowers are 

 not as regular as the forget-me-not. In the viper's 

 bugloss, for instance, the corolla already shows signs 

 of bilateral symmetry, i.e. the top and the bottom have 



1 Fig. 80 — I shows the corolla of the forget-me-not; 2, of the viper's 

 bugloss; 3, of thefigwort; 4, of the wild thyme; 5, of the sage. All 

 the coroUae are spHt along the lower Up and stretched out. The corolla 

 of the sage is also cut along the upper lip. 



