CETRARIA. ICELAND MOSS. 207 



typical branched stone cells. Leaves with similar stone 

 cells have been found, and these are frequently used. 

 The Imperial tea of the Chinese is one of these, but in 

 this the stone cells are more regularly oblong, or squarish. 

 The leaves most, often used are those of the horse-chest- 

 nut, beech, poplar, apple, ash, elder, hawthorne, fire-weed, 

 etc.* 



HERBS AND FLOWERS. 



The general structure of herbs and flowers does not 

 admit of ready generalization. In the most typical forms 

 the structures of stem, leaf, etc., conform to structures 

 already described under the general headings of leaf and 

 woody structures. In addition, however, herbs and 

 flowers contain cells characteristic of the reproductive 

 organs, pollen and seed structures. These structures 

 introduce a far greater variety into the study of these 

 powders, while at the same time offering more differential 

 characters. 



CETRARIA. ICELAND MOSS. 



''Cetraria tslmtdtca (Linne), Acharius (class. Lichens)." 

 U.S. 



This is a lichen growing plentifully throughout the 

 temperate zone; in the North, on the plains; in the 

 South, on the mountains. 



Description. — The membranous thallus is thin and 

 cartilaginous, 5 to 10 cm. long, obscurely dichotomously 

 divided, the edges of the lobes rolled up below with 

 irregular ciliate margins above. The base is red, the 

 under convex side of the lobes gray with white points, the 

 upper side olive green or brown. The apothecia, seldom 

 present in the dried drug, are i cm. broad, saucer- 

 shaped, reddish-brown, situated at the ends of the lobes. 



♦ M. Bninotte: De la determination histologique des falsifications du 

 th6. Thdae Ecole de Pharamcie de Nancy, 1883. 



