PLACE AND NATURE OF nUKlIN 



163 



oldest existing; ])liyt()nu'r ])erislios each year as a suceessi^■e a])ical one 

 is formed (Fij;. 450, h). 



Forms of Rhizomes. — Rhizomes are so inimeroiis and important in 

 pharmacy that their characters call for special attention. They are 

 classed as short or elongated, the former term referring to those 



4S2. 



Forms of rhizomes: Fig. 447. Convallariti, with :iiiiiular roots: «, terminal l)ii<l. 448. Cimicifiii/n, 

 its cup-shaped stcni-scars much elevated. 449. Podophyllum, its intcrnodes elongated. 450. Poly- 

 poria/UOT, its cup-shaped scars depressed. 451. /n's, its roots aggregated at one end. 452. Acorus, with 

 V-shaped leaf-soars. 



the extreme length or shortness of which fall within certain fairly 

 defined and restricted limits; the latter, those which cither j^ossess an 

 indefinite extension, or the definite length of which is a great many 

 times their thickness. Terms indicati\e of their form and consistency 

 do not differ materially from those a])i)lied to other stems and to roots. 

 They are almost always sympodial. They are very subject to flatten- 



