HAMAMELIS 



291 



bark with a continuous layer of stone cells, the walls being very thick, 

 lamellated and with large simple and branching pores; parenchyma 

 of primary cortex containing either reddish-brown amorphous tannin 

 masses, or very small starch grains; inner bark with medullary rays 

 usually 1 cell wide, occasionally 2 to 5 cells wide, separating the bast 

 fibers which occur in tangentially elongated groups, plates of paren- 

 chyma and sieve tissue; bast fibers with thick, more or less lignified 



A _ 



FIG. 130. Hamamelis virginiana: A, transverse section of twig: K, cork; 

 H, cells of hypodermis with simple pores, the cells containing chloroplasts 

 and small starch grains; Co, calcium oxalate crystals; Cf, crystal fibers; 

 F, bast fibers with thick, strongly lignified walls; S, sieve cells; M, medullary 

 rays; C, cambium; W, wood fibers; T, tracehae. B, tangential section of a 

 twig showing stone cells (St), crystal fibers Cf), and thick- walled bast fibers 



walls and associated with crystal fibers usually consisting of mono- 

 clinic prisms, 0.015 to 0.040 mm. in length; adhering wood of tracheae 

 having bordered pores, numerous strongly lignified wood fibers with 

 prominent oblique slit-like, simple pores or bordered pores and med- 

 ullary rays 1 celt wide, the walls being more or less lignified, with 

 numerous simple pores and the lumina occasionally filled with starch. 



