458 



BOTANY AND PHARMACOGNOSY. 



and sieve alternating with white parenchyma, wood lemon-yellow, 

 I to 4 mm. thick, porous and non-radiate ; odor slight ; taste bitter. 

 Inner Structure. See Figs. loi, D ; 197a. 



Fig. 197a, Taraxacum: A, transverse section of root showing cork (k), parenchyma 

 containing inulin (p) , laticiferous vessels (1) , phloem groups (s) composed of sieve and laticif- 

 erous vessels, cambium (c), tracheae (t), modified, non-lignified wood-fibers (Ersatzfasem) 

 (w); B, longitudinal section of xylem showing several of the reticulate tracheae and the 

 modified wood-fibers with oblique pores that are apparent in preparations made with chlor- 

 zinc-iodide; C, longitudinal section of a phloem group showing branching laticiferous vessels 

 (1) , sieve cells (s) , containing sphere cryitals of inulin. 



Constituents. The drug contains about 0.05 per cent, of a 

 bitter principle, taraxacin, which gives reactions with certain of 

 the alkaloidal reagents ; it also contains two resins, one soluble in 



