HYDRASTIS 



291 



ness ; although they appear to be horizontal and creeping they are 

 often oblique or even erect, as is indicated by the direction of the 

 buds with which some of the branches terminate, as well as by the 

 presence of rootlets on the (apparently) upper as well as under surface. 

 They are knotty, tortuous, and rough, frequently giving off short 

 upright branches terminated by cup-shaped scars left by the aerial 

 stems of previous years. These branches usually bear distinct 

 encircling scars of cataphyllary leaves, and similar scars are borne 

 by the rhizome also, although there they are less distinct. 



Thin, shrivelled, wiry, brittle roots of the same colour as the 

 rhizome proceed from all parts of it, but especially from the 

 lateral and ventral surfaces. 

 Many of them break off, 

 leaving small protuberances on 

 the rhizome, which is often 

 therefore rough and compara- 

 tively free from roots. 



The rhizome is hard, and 

 breaks with a short resinous 

 fracture. The transverse sec- 

 tion varies in colour from dark 

 yellow to very dark yellowish 

 brown, and exhibits a com- 

 paratively thick bark 1 and a 

 ring of bright yellow, somewhat 

 distant narrow wood-bundles 

 surrounding a large pith. The 

 root also exhibits a dark 

 bark and small, bright yellow 

 wood. 



The drug has a faint but 



characteristic odour ; when it is chewed a bitter taste is developed 

 and the saliva is coloured yellow. 



The student should observe 



(a) The yellow colour, 



(b) The structure visible in the transverse section when examined 



with a lens. 



(c) The characteristic odour ; 



1 I have employed the term ' bark ' to designate the collection of tissues exterior 

 to the cambium of the rhizome and root as well as of the stem (compare p. 233). 

 The Pharmacopoeia has adopted the word ' cortex,' but this is liable to misinterpre- 

 tation owing to the restricted sense in which the term is employed by modern 

 botanists. For the tissue exterior to and including the endodermis (in monocotyle- 

 donous rhizomes) I have used the term * cortex,' which is correct both in its ordinary 

 and its botanical sense. 



FIG. 143. Hydrastis rhizome. Natural 

 size. (PharmaceuticalJournal.) 



