NUCLEUS-SHEATH. 207 
circle, in other cases they are dispersed, as is the case in Rhizoma 
Veratri and Rhizoma Caricis, or to a still greater extent in Tuber 
Aconiti, or but a single central bundle is present, as in the root- 
lets of Veratrum. 
The cells of the sheath are not always elongated, but often 
Fig. 124,—Transverse section through the endodermis of Vera-Cruz Sarsaparilla. 
nearly cubical or only slightly extended. They are also often 
thin-walled, contain starch, and are then called starch-layer or 
starch-sheath. 
Fic. 125,—Transverse section through the endodermis (k) of Rhizoma Galange; a; 
fibro-vaseular bundles; r, resin-cells; m, fundamental tissue. 
The walls of the endodermis which are directed toward the 
axis are usually thickened; in the lateral walls this is also 
sometimes the case, so that the lumen or cavity, for instance in 
the Vera Cruz Sarsaparilla (Fig. 124), becomes very much con- 
