CHAPTER III 



INFLUENCE OF EXTERNAL CONDITIONS ON GROWTH 



AND CONFIGURATION 1 



§i. Dependence of Growth and Configuration upon Temperature.— 



Medium temperatures 2 are most favorable for growth, which ceases with very 

 high and with very low temperatures. The following table shows the incre- 

 ments of elongation of three plants for a forty-eight hour period, at various 

 temperatures. 



1 [On plant movements in general, see: Pringsheim, Ernst G., Die Reizbewegungen der Pflanzen. 326 p. 

 Berlin, 1912.] 



2 Koppen, W., Warme und Pflanzenwachsthum. Bull. Soc. Imp. Nat. Moscou 43 /7 : 41-iro. 1870. 

 Sachs, J., Physiologische Untersuchungen uber die Abhangigkeit der Keimung von der Temperatur. Jahrb. 

 wiss. Bot. 2 : 338-377. i860. [Lehenbauer, P. A., Growth of maize seedlings in relation to temperature. 

 Physiol, res. 1: 247-288. 1914. Also see: Fawcett, H. S., The temperature relations of growth in certain 

 parasitic fungi. Univ. Calif. Pub. Agric. Sci.4: 183-232, 1921.] 



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