224 PLANT ANATOMY, 
other in a compartment-like form. Very frequently this num- 
ber is not considerable, so that the medullary ray, upon a trans- 
. 
———_ cae 
Giipecennes SS 
$$ ZOOS oOoOvoS oS: 
Seer —— 
Fie. 140.—Cells of the medullary rays, consisting of one and three rows, cut trans- 
versely; tangential longitudinal section of a dicotyledonous stem. 
verse section, which is made vertical to its surface of length (tan- 
_ gential to the surface of the stem), represents a cleft filled with 
Fie. 141.—Medullary rays from Lignum Juniperi, consisting of a single row of 
cells (a). 
A, Tangential longitudinal section, a medullary ray. 
Cc. Transverse section through the wood of the root, a medullary ray; c, annual rings. 
parenchyma (Fig. 140). In breadth the medullary rays some- 
__ times present but asingle row of cells, as, for instance, in Lignin 
