CAPSELLA BURSA-PASTORIS. 231 



b. Sections of stomata. 



4. Several rows vl parenchyma cells. 



5. Usually one row of tolerably large, nearly empty paren- 

 chyma cells, the bundle sheath (best distinguished in 

 section from growing plant). 



6. The masses of fibrous tissue rising between the outer 



portions of 



7. The fibre-vascular bunJlcs ; selecting one of the largest 

 of these, note 



a. The arch of bast fibers ; compare this region with 

 the same in smaller bundles. 



b. Beneath the arch a cluster of smaller irregular cells, 

 soft bast. 



c. The trachcary tissue and wood fibers composing the 

 xylem. 



S. The position and extent of the/////, the regularity of 

 the cells and the intercellular spaces. 



9. Draw a segment of the section containing at least one 

 bundle. 



Make a radial longitudinal section, including a fibro-vas- 

 cular bundle, 7 examine with a high power and note 



10. The epidermal cells. 



11. Parenchyma. 



12. Bundle sheath of squarish cells. 



13. The bast fibers, length and nature of walls. 



14. Soft bast, shape and walls. 



15. Tracheary vessels, variously marked. 



1 In a section which passes between fibre-vascular bundles, the same 

 regions will be noted, except that 13, 14, 15, 16 are replaced by abundant 



fibrous tissue. 



