PLANTS OF THE INDIAN DESERT. 39 



MENISPERMACEAE. 



Cocculus cebatha DC. —Figs. 1, 2. (p. 39)— Epidermis of the 

 leaf composed of thin-walled tabular cells. Stomatu occurring on 

 both the surfaces. Subsidiary cells accompanying the guard-cells. 

 Mesophyll composed wholly of palisade cells. Internal glands absent. 

 Pith cells containing clusters of acicular crystals of oxalate of 

 lime. Clothing hairs bicellular and curved. Glandular hairs absent. 

 Veins embedded and enclosed in green sheaths. Axis slightly ribbed, 

 ribs strengthened by a few sclerenchymatous fibres. Epidermal cells 

 of the axis tabular with outer walls greatly thickened and cuticularis- 

 ed. Cortex formed of chlorophyll containing parenchyma. Pericycle 

 composed of large groups of stone-cells. Wood formed of xylem bund- 

 les separated by broad medullary rays extending to the cortical 

 chlorenchyma. Groups of cells resembling bast fibres on the inner 

 face of the xylem bundles. Pith composed of thick-walled cells. 



Structure of the leaf 



Epidermis is composed of tabular cells, with outer walls flat and 

 a little thickened. Lateral and inner walls are thin and the former 

 are straight. Stomata are accompanied by subsidiary cells and are 

 more numerous on the under-surface. Guard-cells are situated on a 

 level with the surrounding cells, with the front cavity slightly depres- 

 sed, or on a level with the surface, fig 1. The mesophyll is composed of 

 a homogeneous tissue of short palisade cells. Internal glands are 

 absent in the leaf as well as in the stem. Oxalate of lime is not found 

 in any form in the leaf. 



Veins are embedded and are enclosed in green bundle sheaths. 

 Veins of the mid-rib, which is prominent above and below, are verti- 

 cally transcurrant above and below by collenchyma; the bundles are 

 protected on the lower side by small groups of stone-cells. 



Hairy covering on the leaf and axis consists of clothing hairs. 

 Clothing hairs are made up of a short thin-walled basal cell and of 

 a long curved thin- walled pointed terminal cell. 



Structure of the axis 



Epidermal cells are small and tabular with outer walls very 

 greatly thickened and cuticularised. Lateral and inner walls are thin 

 and the former are straight. The axis is slightly ribbed, the ribs being 

 strengthened by a few sclerenchymatous fibres. 



The cortex is formed of chlorophyll containing parenchyma which 

 extends to the medullary rays between the groups of stone-cells of the 



