THE COLTSFOOT 



ation ; once the leaf gets clear^ it spreads out its 

 broad surface (sometimes eight inches across) to 

 the sunhght, and there it absorbs carbon dioxide, 

 or more famiharly, carbonic acid gas, from the 

 atmosphere. The carbon derived from this impure 

 gas is then chemically united with the ^Yatery sap 

 supplied from the soil by the roots, the ultimate 

 product of this combination being energy-yielding 

 starches, oils, and similar materials. These life- 

 giving products are at once conveyed below ground 

 and stored in the rootstock, and there are held 

 in reserve until early in the next year, when they 

 will be utilised in the production of flower and 

 leaf shoots. Thus the work of the summer foliage 

 provides the early growth of the next season. 



Now the building of these life-giving materials 

 from inert carbonic acid gas, or carbon dioxide and 

 water, can only take place in the tissues of the 

 green leaves under the influence of sunlight. 

 Hence we see why the coltsfoot requires large 

 and expansive leaves, and we account for their 

 persistence in monopolising all the available sun- 

 light. Flowering stems bearing rich pollen, and 

 seeds containing starches and oils, cannot be 

 produced so early in the season as those of the 

 coltsfoot without a large and rich reseiTC of 

 material ; and the wily coltsfoot has learnt its 

 lesson well. Also, by selecting ground on which 

 other plants find it difficult to thrive, the coltsfoot 

 can spread out its leaves in unrestricted exposure 

 to the sun's rays ; hence their large size. 



Of plants which grow in open spaces where 



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