FIG. 225. Pinkroot (Spigelia marilandica) : A, transverse section of root showing 

 epidermis (e), parenchyma containing starch (p), peripheral layer of central 

 cylinder (I), the endodermis (e), a pericambial layer (i). The central cylinder 

 consists of six to eight radial fibrovascular bundles, and some of the tracheae 

 contain a brown gummy substance. B, transverse section of rhizome 

 showing epidermis (0, the outer wall of which contains a yellowish-brown 

 substance, parenchyma (p) of cortex containing starch, sieve of cortex (s), 

 cambium (c), tracheae (i), tracheae (r) containing globular or somewhat 

 irregular yellowish-brown masses, trachaids (h), internal sieve groups (s), 

 parenchyma of pith (p') containing starch. C, longitudinal se'ction of the 

 woody part of the rhizome. D, isolated starch grains, which are from 0.020 

 to 0.005 mm. in diameter. 



