DIFFERENT STAGES OF GROWTH OF THE OAT-PLANT. 49 



consumes the food which should have served to form 

 buds and new roots, or to increase the store of organisa- 

 ble matter in the roots. Thus stunted in its develope- 

 ment, the root supplies less food to the plant in spring, 

 as it takes up and gives out less in proportion to its 

 smaller absorbent surface and more limited supply 

 stored up in it ; and it retains the same feeble character 

 in the succeeding periods of vegetation. The agricul- 

 turist endeavours to meet the difficulty by grazing down 

 or cutting these feeble plants ; the formation of buds 

 and roots hereupon begins anew, and if the external 

 conditions are favourable, and the plant has time to 

 fill the root with a fresh store of organisable matter, the 

 normal conditions of growth are, in the agricultural 

 sense, restored. Summer corn maintains, in the several 

 periods of its developement, the same character as win- 

 ter corn ; only these periods are of much shorter dura- 

 tion. 



Ahrend's study of the oat-plant in its several stages 

 of growth is instructive in this respect. He determined 

 the increase in combustible and incombustible constitu- 

 ents during the following periods : from germination to 

 the beginning of shooting (end of the first stage, 18th 

 June) ; from this time to shortly before the end of 

 shooting (second stage, 30th June) ; immediately after 

 flowering (third stage, 10th July) ; the commencement 

 of ripening (fourth stage, 21st July) ; finally, to perfect 

 maturity (fifth stage, 31st July). On the 18th June 

 the plants were on an average* 31 centimeters high (1J 

 inch), the three lower leaves were nearly expanded, the 

 two upper leaves were still folded up. Of the stalk- 

 joints the three lower alone had an appreciable length 

 (1, 2, and 3 centimeters), the three upper had but a "ru- 

 dimentary existence. Twelve days after (on the 30th 

 June) the plant had attained double the height (63 cen- 

 timeters) ; and ten days after this again, on the 10th 

 July, after flowering, it had reached 84 centimeters. 



1,000 plants respectively produce in grammes : 

 3 



