28 



PARENCHYMA. 



Parenchyma of the Leaf. This is a name applied to all 



the rest of the leaf -blade after taking out the epidermis, the fibro- 

 vascular bundles, and the hypodermal fibers. It presents three 

 forms, which are quite distinct: 



a. Cells containing chlorophyll and found in the leaves of all 

 grasses without exception. 



J. Cells without color inside, found in certain species only. 



c. The star shaped and branching cells found in the air canals 

 of species (Fig. 10.) more or less aquatic. 



The chlorophyll-bearing parenchyma is of two sorts : 



a. Where the grains are rather large and compact. 



J. Where some of the chlorophyll is in the form of grains, and 

 some of it is diffused more or less like jelly. 



Where a part of the chlorophyll is more or less diffused, the 

 rest is in cells which form concentric cylinders, or the cylinders 

 may be open in one or two places. 



FIG. 46. Section of a blade o Bnuteloua Harvardii, showing some rlosed and some 

 open cylinders of cells containing grains of chlorophyll. (Sud worth.) 



Fro. 47. Section of part of a blade of Spartina stricta var., showing large cells of 

 parenchyma destitute of chlorophyll; these are situated above the flbro- vascular 

 bundles, and in the middle of the lobes which extend upward. 1 x 34.-<Sudworth.) 



