PLAN* BIOGRAPHIES. 211 



table-cloth. By this ingenious device the colts- 

 foot manages to keep its evaporation pores dry 

 and open, in spite of its damp and moisture- 

 laden situation. One may say, indeed, that 

 every point in the structure of every plant has 

 thus some special purpose; indeed, one large 

 object of the study of plants is to enable us to 

 understand and explain such hidden purposes in 

 the economy of nature. 



During its early life, once more, the young 

 plant of coltsfoot is constantly engaged, like the 

 whitlow-grass and the agave, in laying hy 

 material fqr. its future flowering "season, jiu't 

 it does not lay by, as they do, in its expanded 

 le aves or other portions of its body visible above 

 g round ; instead of that, it puts forth a creeping 

 underground 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 described, to work 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 subterranean stem, which grows 

 horizontally instead of upward. During the 

 summer the coltsfoot lays by in this buried 

 root-stock quantities of rich material for next 

 year's leaves and for its future flowers. 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 underground 

 stem, and send up tall naked scapes or flower- 



