[Vol. 10, 1923] 



384 ANNALS OF THE MISSOURI BOTANICAL GARDEN 



Explanation of Plate 



PLATE 18 



a. Cross-section of Bryophyllum leaf showing vein. 



b. Camera-lucida drawing of vein. 



c. Further division of small phloem cells of vein. 



d. Regenerated root development from small cells of vein 



