142 



PLANT ORGANS OR PARTS OF PLANTS. 



of the powder of aconite. They are elongated, varying 

 from two to four times as long as broad ; the walls are 

 markedly thickened and the pores are simple and deep; 



Fig. 34. — Aconite. 

 Cross-section of tuber of Aconiium napellus: p, Parenchyma; e, 

 endodermis; sr, cortex; c, cambium, stone cells at periphery, vessels 

 within the cambium (Tschirch). 



they are usually colored brownish. The general size 

 is from 20 to 60 microns. 



There is little characteristic of the parenchyma; it 

 varies greatly in size in the different parts of the tuber, 



