CHAPTER III 



INFLUENCE OF EXTERNAL CONDITIONS ON GROWTH 



AND CONFIGURATION 1 



§*. 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. 



The minimum, optimum and maximum temperatures for the growth of 

 several different plants are shown in the next table. This table shows clearly 



Horde um vulgare (barley) 



Sinapis alba (white mustard) 



Lepidhun sativum (garden cress) 



Phaseolus mu'tijlorus (scarlet-runner bean) . 



Zea mays (maize) 



Cucurbiia pepo (gourd, squash) 



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. Xat. Moscou 43": 41-110. 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, 1014. Also see: Fawcett, H. S., The temperature relations 

 of growth in certain parasitic fungi. Univ. Calif. Pub. Agric. Sci. 4: 183-232. 1921.I 



253 



