104 POWDERED VEGETABLE DRUGS 



DESCRIPTION OF PLATE II 



FIG. 12. Types of Crystals of Calcium Occurring in Different Plants. 1. A 

 parenchyma cell containing a bundle of needle shaped (acicular) crystals of calcium 

 oxalate (raphide). 2, 3, 4, Acicular crystals differing in length, as they occur in Scilla 

 and in other representatives of the liliaceous groups of plants. 5. Much elongated 

 prismatic crystals as they occur in Quillaja and in Iris florentina. 6. Prismatic crystals 

 very widely distributed in the plant kingdom. 7. Elongated prismatic crystals. 8. 

 Twin crystals as they occur in Ulmus bark. 9. Very large aggregate crystals very 

 widely distributed in the vegetable kingdom. 12, 13. Very minute prismatic (pyrami- 

 dal) crystals as they occur in Belladonna. 14. Prismatic crystals as they occur in 

 Hyoscyamus and in other plant groups. 



Calcium oxalate crystals are among the highly diagnostic structural characteris- 

 tics of drug plants and should be studied not only as to form but also as to size. They 

 are not dissolved in the usual mounting media and are not destroyed by heat. They 

 dissolve slowly in the stronger acids (hydrochloric acid) . 



FIG. 13. Types of Bast Cells as They Occur in Barks and in Other Plant Parts. 



1. Shorter bast cell as they occur in the cinnamon barks. 2. Typical bast cell (showing 

 a portion of a cell only) as they occur in willow bark, in Ulmus, in Mezereon, etc. 3. 

 Branching bast cells as they occur in Quillaja in Prunus bark. 4. Greatly thick- 

 ened sclerenchymatous bast cells as they occur in the Cinchonas. 



FIG. 14. Types of Sclerenchyma (Stone) Cells. 1. Typical sclerenchyma cells 

 as they occur in the endocarp of drupaceous fruits and nuts. 2. Elongated bast- 

 like sclerenchyma cells. 3. Thin-walled typical sclerenchyma cell. 4. Scleren- 

 chyma cell with unequally thickened walls as they occur in the cinnamons. 5. Large 

 thin-walled sclerenchyma cells as they occur in the seed coat of Amygdala. 6. Branch- 

 ing sclerenchyma cells as they occur in tea leaves and in peanut exocarp. 7, 8, 9, 

 Forms of sclerenchyma cells. 



FIG. 15. Typical Sclerenchyma Cells (in groups) as they occur in the pulp of the 



pear. 



