CHESTNUT 



171 



mental differences in their morphology they have been divided 

 into three families, viz.: 1, The Ulmaceae, or Elm Family; 2, the 



FIG. 73. Castanea. A, transverse section of leaf through the midrib showing 

 upper epidermis (Ue); palisade layers (Ps); loose mesophyll (Ms); bast 

 fibers (#/); sieve (L); tracheae (T); parenchyma (P); non-glandular hairs 

 (H) ; rosette aggregates of calcium oxalate (Ca) ; stoma (So) ; lower epidermis 

 (Le). B, stellate hair. C, fragment of leaf showing 2 stomata. D, frag- 

 ments of powdered drug showing crystal fiber (C/); bast fiber (Bf)\ stone 

 cells (St); parenchyma (P) containing calcium oxalate (Ca); non-glandular 

 hair (H). Drawing by Haase. 



Moracese, or Mulberry Family, and 3, the Urticacese, or Nettle 

 Family proper. By some authors the plants of the genera Cannabis 

 and Humulus are separated and brought under a fourth group, 



