42 MICHIGAN ACADEIMY OF SCIENCE. 



3. The transition from root to In'pocotyl so far as it involves the 

 relative position of xylem and phloem takes place between the two 

 whorls of lateral roots. 



4. Koots of the upper whorl lie opposite the spaces between the 

 bundles and not opposite the bundles, but tlie^' are directly over the 

 roots of the next lower whorl. 



5. Just above the upper whorl of secondary roots the number of 

 fibro-vascular bundles is four. Each of these separates into two approxi- 

 mately equal ]>arts. and two pairs <»f these eight unite so as to leave 

 only six in all. This number continues up to the cotyledons. 



6. The point above the upper whorl of secondary roots at which the 

 four bundles bepin to separate into eight varies in ditferent individ- 

 uals from 1 to 10 mm. The whole change from four to eight, then to 

 six bundles may take place within 8 mm. in length of the hypocotyl, 

 though in one case examined it extended through a length of 30 mm. 

 The smaller numbers are more common. 



