HISTOLOGY 



37 



bands lying on the lower side are in contact with the chlorophyl- 

 lous layer, whereas the upper bands are either in contact with this 

 layer or separated from it by a few parenchymatous cells. 



All the vascular bundles in the leaves of Eragrostis Willde- 

 noviana are provided with sclerenchyma on both the sides. The 



Fig. 56. — Transverse section of a part of the leaf of Eragrostis Willdenoviana. x 30 

 I. Vascular bundle ; 2. sclerenchyma ; 3. motor cells 



lower band of the primary vascular bundles is continuous with the 

 vascular bundle, the chlorophyllous layer being open below. The 

 upper bands of the primary and the lower bands of the secondary 



Fig. 57. — Transverse section of a portion of the leaf o r Eragrostis Willdenoviana. x 150 



I. Motor cells; 2. stomata ; 3. sclerenchyma; 4. chlorophyllous layer ; 5. vascular 

 strand cut through ; 6. hair. 



vascular bundles just touch the chlorophyllous layer. In the 

 secondary bundles the sclerenchyma band above is separated from 

 the chlorophyllous layer by two layers of parenchyma. In the 

 case of the 'eaves of Panic urn flavidum, P. colonum, P. fluitans and 

 Pennisetum cenchroides the sclerenchyma is separated from the 

 chlorophyllous layer by layers of parenchyma. 



BMW 



rXrjj > u _. 



&*%2^—* — ' — fc — T 



FIG. 58. — Transverse section of a part of the leaf of Panicum colonum. 

 I. Vascular bundle ; 2. sclerenchyma ; 3. motor cells, , 



30 



Even from the few examples dealt with above, it is obvious that 

 the range of variation of sclerenchyma in leaves is very great. In 

 the leaves of Aristida sctacca there is a considerable amount of 

 sclerenchyma whilst in some leaves such as those of Panicum 



