DIFFERENT STAGES OP GROWTH OF THE OAT-PLANT. 35 



limited supply stored up in it ; and it retains the same 

 feeble character in the succeeding periods of vegetation. 

 The agriculturist 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 ex- 

 ternal 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 winter corn ; 

 only these periods are of much shorter duration. 



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

 growth is instructive m this respect. He determined the 

 increase in combustible and incombustible constituents 

 during the following periods : fi'om germination to the be- 

 ginning 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 riperdng (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 (1^ 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 nidimentary existence. Twelve days 

 after (on the 30th June) the plant had attained double the 

 height (63 centimeters) ; and ten days after this again, on 

 the 10th July, after flowering, it had reached 84 centi- 

 meters. 



1,000 plants respectively produce in grammes : — 



