194 THE STORY OF THE PLANTS. 



During its early life, once more, the young 

 plant of coltsfoot is constantly engaged, like the 

 whitlow-grass and the agave, in laying by mate- 

 rial for its future flowering season. But it does 

 not lay by, as they do, in its expanded leaves or 

 other portions of its body visible above ground ; 

 instead of that, it puts forth a creeping under- 

 ground stem or root-stock, which pushes its way 

 sideways through the tough clay soil, often for 

 several feet, and sends up at intervals groups of 

 large roundish leaves, such as I have already de- 

 scribed, to w^ork above ground for it. You might 

 easily take each such group for a separate plant, 

 unless you dug up the root-stock and saw^ that 

 they were really the scattered foliage of one sub- 

 terranean stem, which grows horizontally instead 

 of upward. During the summer the coltsfoot lays 

 by in this buried root-stock quantities of rich ma- 

 terial for next year's leaves and for its future 

 flow r ers. In winter the leaves die down, and you 

 see not a trace of the plant above ground. But 

 in very early spring, as soon as the soil thaws, 

 certain special buds begin to sprout on the under- 

 ground stem, and send up tall naked scapes or 

 flower-stems, usually growing in tufts together, 

 and each crowned by a single large fluffy yellow 

 flower-head. These stems are covered below by 

 short purplish scales ; and their purple colouring 

 matter enables them to catch and utilise to the 

 utmost the scanty sunshine that falls upon the 

 plant in chilly March weather. For this particu- 

 lar colouring matter has the special property of 

 converting the energy in rays of light into heat 

 for warming the plant. The scape is also wrapped 

 up in a sort of cottony wool, which helps to keep 

 it warm; and the unopened flower-head turns 



