ROOT HAIRS AND GROWTH 



363 



a 



Fig. 4._ (a) Photograph of the radish root in the root hair zone. (If) Photograph of the popcorn root in the 

 root hair zone, (c) Root hair of popcorn photographed at 15-minute intervals. Spaces between the upper 

 five photographs show lateral movement. The lower five show root hair elongation only. (d~) Root hair of 

 radish photographed at 15-minute intervals for i.\ hours. The spaces between the upper seven photographs 

 show the amount of lateral movement during each interval. The lower four show root hair eloneation only 

 (After Jeffs.) & 7 ' 





