ROOT GROWTH AND TEMPERATURE 



329 



TABLE 5 

 Root growth of mesquite seedlings at a soil temperature of 35°C., in millimeters. 



* First fifteen hours after setting up the experiment. 

 t Fourteen hours interval. 



TABLE 6 



Root growth of mesquite seedlings, soil temperature 24° io 25°C., in millimeters, for 



12 hour periods 



* Average of two readings. 



ment started. In plant 41 three high growth points appear on 

 the curve, and they are of about the same value. In 45 hours 

 the root of plant 41 increased 110 mm. in length. This, how- 

 ever, is not the highest rate of root growth observed in the 

 species. The root of one plant, not elsewhere reported on in 

 this paper, grew 51 mm. in 12 hours, which is the most rapid 



