PLATE 19 
CRYSTAL-BEARING FIBRES OF BARKS 
I. Frangula (Rhamnus frangula, L.). 
2. Cascara sagrada (Rhamnus purshiana, D.C.). 
3. Spanish licorice (Glycyrrhiza glabra, L.). 
4. Witch-hazel bark (Hamamelis virginiana, L.). 
