454 POWDERED VEGETABLE DRUGS 



159. PULSATILLA. PulsatiUa. 



Fl. ex. 30. 

 Pasque flower, E. Klichenschelle, G. Pulsatille, Coquelourde, Fr. 



The flowering herb of Anemone pratensis L. Ranunculacese. 



Greenish. 



Fragrant; hay odor. 



Somewhat pungent. 



Vertical wall of lower epidermal cells wavy, of upper epidermis only 

 slightly so. Stomata above and below. Some of the leaf parenchyma 

 cells filled with crypt ocrystalline calcium oxalate. Long (500 microns) 

 single celled, thick-walled, simple trichomes and some single celled. 

 Indian club-shaped, thin-walled glandular trichomes. Some scleren- 

 chymatous cells. 



160. (Fig. 157). PYRETHRUM INSECT POWDER. Insect 



Powder. 



The partially expanded flower heads of Pyrethrum species. Com- 

 positse. 



Fine powder. Non-characteristic feel. 



Yellowish brown. 



Somewhat aromatic. 



Somewhat pungent. 



P. ^roseum, P. Marshallii and P. cinerariaefolium are the official 

 species as named by the U. S. Insecticide Board. The histology of the 

 three species is closely similar. Vascular tissue, parenchymatous 

 tissue, " T-shaped trichomes (basal cells usually broken and removed, 

 leaving the tapering pointed end cell plainly to be seen). The pollen 

 grains (spherical with incompletely developed conical projections on 

 exine) should be abundantly present, though mostly immature. 

 Some typical sclerenchyma cells (from torus) ; also aggregate crystals. 

 A good quality of insect powder should show on an average at least 15 

 immature pollen grains in the field of the compound microscope (high 

 power No. 2 oc. and No. 7 obj.). 



Ash 6 to 7 per cent. Impurities (inclusive of pyrethrum stems) 

 should not exceed 15 per cent. 



Very commonly adulterated. Most common adulterants are 

 pyrethrum stems (excess of fibrous tissue and pollen grains few or none) 

 also suspect old flower heads (few mature pollen grains, abundant seed 

 tissue, sclerenchyma cells excessive); flower heads of related species, 

 of calendula, of chamomile, etc.; sawdust, curcuma, mustard hulls, 

 flour, corn meal, etc. A standard based upon the number of pollen 

 grains present should be adopted. An insect powder showing less 

 than an average of 3 to 5 immature pollen grains to the field (high 

 power) of the compound miscroscope should be rejected. 



