Ch. IV, 3] 



anato:my of stems 



129 



Fig. So. — The cellular anatoni}', in corresponding cross and longitudirial 

 sections, of a young stem of Arlslolochia Sipho. a tT\ining vine; X 50. 

 In the center, the pith; next three fibro-vas- 

 cular bundles, showing the xylem with 

 ducts, the rectangular nucleate cells of 

 the cambium, and the phloem, 

 marked by sieve-plates and nu- 

 cleate cells; next the sclerenchyma 

 ring, with the starch sheath 

 just outside; then the cor- 

 tex, consisting of chlo- 

 renchyma and coUen- 

 chjTua ; and finally 

 the epidermis. 



