100 POWDERED VEGETABLE DRUGS 



I 6 Centric. 

 2 6 Excentric. 



2 4 Compound. In twos, threes and fours. 

 3 4 Aggregate, as in oats and rice. 

 2 3 Crystals of calcium oxalate. 

 I 4 Crystal dust or powder. Rare. 

 2 4 Prismatic. Comparatively rare. 

 3 4 Acicular. Raphides. Larger and smaller. 

 3 3 Cystoliths. Rare. 

 4 3 Mucilage cells. 

 5 3 Resin. 



6 3 Coloring matter. 

 4 1 Vascular tissue. 



I 2 Endoderm. Cells sometimes diagnostic. 

 I 3 Size and form of cells. 

 2 3 Thickness of cell-walls. 

 3 3 Contents. 



2 2 Ducts. All possible forms. 

 3 2 Phloem. 



I 3 Sieve tissue with contents. 

 2 3 Conducting cells. 

 4 2 Parenchyma. 

 5 2 Bast, 



6 2 Tracheids. Often important. 

 I 3 Size and form. 



2 3 Size, number and form of pores. 

 5 1 Woody tissue. Variable in amount. 

 I 2 Wood fibers. 

 2 2 Tracheids. 



3 2 Ducts. Note form, size and markings. 

 4 3 Medullary rays. 



I 4 Size and form of cells. 

 2 4 Number of layers. 

 3 4 Cell-contents. 



5 3 Cell-contents. Crystals, some starch, etc. 

 6 1 Pith tissue. Usually deficient. 



VI. STEMS. 



I 1 Epidermis. Usually present. See leaf. 



2 1 Hypoderm. Not generally present. See leaf. 



3 1 Chlorophyll-bearing parenchyma. 



4 1 Collenchyma. Usually typical. In interrupted patches. 



