RHUBARB SPROUTS. 47 



well as of long sprays in hedgerows and on young rose- 

 bushes. As soon as the leaves are fully expanded, the 

 green chlorophyl begins to develop, and they rapidly 

 assume their true hue and their active life ; but if they 

 are kept in the dark, or prevented from normally de- 

 veloping, they go on retaining their original bright col- 

 ors for an indefinite period. 



It seems most probable that in all cases the oxidation 

 of green leaves, stems, or other parts of plants, produces 

 bright red, yellow, and orange coloring matter. We are 

 all familiar with this fact in the instance of autumn 

 hues, where Mr. Sorby has shown that the pigment is 

 chemically nothing more than an oxidized form of the 

 ordinary chlorophyl. So it is in the case of both flowers 

 and fruits, which are purely expensive structures, pro- 

 duced for the most part from reservoirs of raw material, 

 such as bulbs, tubers, starchy root-stocks, or permanent 

 stems, and thus exactly resembling the red or purple 

 shoots of the peony, the rhubarb, the sea-kale, and the 

 hawthorn bushes. Every one knows that fruits are at 

 first green, and only grow colored as they ripen that is 

 to say, as they oxidize. Mr. Sorby has shown that in 

 flowers, too, the coloring matter is at first green, and 

 exactly resembles that of ordinary leaves ; but as they 

 grow older they also get oxidized, and so assume their 

 bright hues. 



In fact, the pigment of the petals in many cases is ex- 

 actly the same, both in color and in chemical composi- 

 tion, as that of the autumn leaves from which the chlo- 

 rophyl has disappeared, or of the young spring foliage 

 in which it has not yet been developed. So that, to put 

 it simply, all plants, whether they produce brilliant 

 fruits and flowers or otherwise, have in them all the 

 material necessary for such a display, and could be in- 



