VICIA, 



23. Histology of Stem. Draw a sector of the same section under the high power, 

 showing : epidermis ; collenchyma ; cortical cells ; endodermis ; pericycle or bast fibres ; 

 phloem ; cambium ; xylem consisting of vessels and parenchyma ; medullary rays ; pith. 



24. Histology of Stem. With a razor cut thin transverse sections of a piece of the 

 stem of a bean, with secondary thickening. While cutting keep the blade of the razor 

 moist with water and float the sections into a watch-glass containing water. Mount 

 the best of them on a slide and examine under the low power. Make a sketch showing 

 the relative positions of the following : epidermis ; cortex, containing isolated vascular 

 bundles ; pericycle, with pericycle fibres opposite each vascular bundle ; vascular bundles, 

 each consisting of phloem, cambium, and xylem; medullary rays; interfascicular cambium 

 with secondary xylem and phloem; pith; air passages between cells of pith and of cortex. 



