SUMMER FLOWERS 



come and gone, when pollination has been effected, when the 

 season is getting on, then the nectaries close up, the feast is 

 over, and the fruit begins to fill. We are aware that nectar is 

 often more than sugar, that it may include balsam and gum, 

 and so forth ; we are aware that a big book might be written 

 about nectaries ; but we are only concerned here in stating the 

 general biological aspect of a very familiar fact the flowers' 

 feasts of honey. 



The second accessory characteristic of the flower is 

 fragrance, to which many insects are extremely susceptible. 

 What is the primary significance of this incense, whose 

 secondary advantageousness is so obvious ? The answer 

 which suggests itself is that the fragrant substances are 

 waste-products in some cases by-products of the essential 

 metabolism that goes on in the plant. It will be remembered 

 we have only to think of woodruff and lavender and pepper- 

 mint that the fragrant substances often occur in leaves, 

 though flowers have made a speciality of their production. 

 The chemists have distinguished a great number of these 

 aromatic compounds, such as the soporific aminoid in haw- 

 thorn ; the benzoloids in mignonette and violets ; the 

 paraffinoids in valerian, pelargonium, and roses ; the 

 turpenoids in orange and lavender ; the strange indoloids, 

 said to arise from broken-up proteids, in aroids, Aristo- 

 lochia, and Rafflesia which attract carrion-loving flies. There 

 are said to be over five hundred of these aromatic compounds 

 on the catalogue, and there are doubtless very many more. 

 For different species, when they are worthy of the name, 

 show individuality in their chemical processes as well as 

 in structure and habit, and it seems not unlikely that we 

 are as near the heart of the matter when we distinguish 

 flowers by their fragrance as when we count the microscopic 

 chromosomes in their nuclei. As with nectar-production, 

 so with fragrance ; there are endless subtleties of adapt a- 



