H4 MAWtf-HAlR FERN". 



here and there between the sieve cells (to be 

 pointed out directly), all filled with granular pro- 

 toplasm and small starch grains. Compare with 

 cortical parenchyma. 



b. The sieve cells ; lying between the main body of 

 phloem parenchyma and the scalariform vessels. 

 Note their angular shape, slightly thickened walls 

 and emptiness, except for a little granular material 

 clinging to the walls. 



c. The scalariform vessels. Observe 



i. That wherever two vessels are in contact their 

 contiguous walls are flattened, and the vessels 

 are therefore irregularly polygonal, having 

 two or three sides much longer than the 

 others. 



ii. That they are thicker at the angles than on 

 the sides, and thus appear to be united only 

 at the angles. 



iii. The narrow slit between the contiguous sides 

 of the vessels. 



iv. The emptiness of the vessels. 



d. The xylem parenchyma; small cells packed between 

 the scalariform vessels, and similar ones near their 

 periphery. Note their contents. 



e. Notice the general arrangement of the tissues, 

 making it a concentric bundle. 



/. Draw sufficient of the fibro-vascular bundle and 

 its sheath to show the different tissues and their 

 relations to one another. 



Cut a longitudinal radial section of the stem in the plane 

 of the leaf stalks. Examine with a low power, and make 

 out 



ii. The epidermis. 



