RHUBARB SPROUTS. 43 



perennials grown from a permanent root-stock ; and in 

 some cases they have been more or less blanched, 

 naturally or artificially, by growing underneath a loose 

 mass of heaped-up earth. If one looks into the flower- 

 garden, one sees the same thing in the sprouting paeonies, 

 whose rich red foliage is more likely, perhaps, to be 

 admired than the very similar leaves of the beet. All 

 these brilliant colours on spring plants are interesting 

 because of the light which they incidentally cast upon 

 the origin of the equally brilliant and far more definite 

 colours of fruits and flowers. 



Those who watch trees and bushes closely must have 

 noticed that the first buds in spring are usually more or 

 less red, or at least reddish or brownish. They must 

 also have noticed that in summer the ends of long grow- 

 ing sprays are likewise ruddy, or purple, or warm brown. 

 Now, at first sight, these facts do not seem to have much 

 connection with another class of facts, such as those 

 noticed above, of which we may take as a typical 

 example the delicate blue or violet tinge on potato-stems 

 allowed to grow in a dark cellar. But when we come to 

 look at them closely, it is clear that they have all one 

 characteristic in common : they are leaves or leaf-stems 

 which are not performing their proper functions. All 

 plants, of whatever sort, when placed in full sunlight 

 develop the active green colouring matter in their 

 leaves the chlorophyll which enables them to analyse 

 carbonic acid in the air, and to store its carbon as starch 

 in their own sap or tissues. When they are kept in the 

 dark, however, or when they are yet too young to have 

 assumed their proper office, they do not contain any of 

 the green colouring matter, and so they look yellow, pink, 



