SUMMER FLOWERS 



WE have seen that the Biology of Summer has for 

 its two main problems the manifold effect of heat 

 and light upon living creatures, and the increasing prepon- 

 derance of reproduction over nutrition, of flower over leaf, 

 of " Love " over " Hunger." Heat, within limits, makes the 

 wheels of life go more quickly round ; it accelerates de- 

 velopment and the lashing of cilia ; it makes egg-cells twin, 

 and it keeps the green flies parthenogenetic ; and it has 

 a hundred other influences. Light promotes assimilation 

 in leaves and slows growth ; it induces pigmentation and 

 quickens our pulse ; it makes Bacteria live so quickly that 

 they die ; and it has a hundred other influences. But our 

 present study is concerned with the growing preponderance 

 of flower over leaf. 



Every one knows that a typical flower is made up of four 

 different kinds of parts, arranged in circles or whorls, one 

 within the other. Outermost are the sepals, making up the 

 calyx ; they are usually firm and green ; they protect the 

 bud and steady the opened flower. Next come the petals, 

 making up the corolla ; they are usually delicate and 

 coloured, often fragrant, and often making nectar ; they thus 

 attract insect-visitors, and they are also useful in protecting 

 the even more important parts farther in. The third whorl 

 consists of the rod-like stamens, whose heads or anthers 

 make the golden-yellow fertilising dust or pollen. The inner- 

 most parts of the fourth tier are the carpels, which bear 

 microscopic eggs, each of which, if fertilised, will develop into 



