164 THE JOURNAL OF INDIAN BOTANY. 



mal cells have outer walls thickened, granulated and convexely arch- 

 ed outwards. Lateral walls are thin and straight. Primary cortex 

 is composed of chlorenchyma. Collenchyma is developed in the ribs 

 of P. Niruri. 



Pericycle forms a loo?e ring of groups of bast fibres in P. Niruri, 

 while E. granulata it is represented by isolated bast fibres. Wood 

 forms a composite hollow cylinder with vessels distributed uniformly 

 in incomplete rows in interfascicular wood prosenchyma. Vessels 

 are more numerous in E. granulata. Medullery rays are uniseriate 

 and numerous. 



Pith consists of very thin-walled cells. 



LILIACEAE. 



Asparagus racemosus Wilkl Var. javanica Bah. — Epider- 

 mal cells with dark-brown granules. Cork subepidermal. Pericycle 

 forming a composite ring of stone-cells. Vascular bundles scattered 

 in a concentric fashion in the ground tissue. Ground tissue formed 

 of cells with walls thin aud lignified. 



Structure of the Axis. — The epidermis consists of tabular cells. 

 Epidermal cells have outer walls a little thickened and are filled with 

 dark-brown granules. Lateral walls are thin and straight. Cork is 

 subepidermal and is formed of thin-walled cork cells. The pericycle 

 forms a composite ring of stone-cells outermost layer of which con- 

 sists of a little larger stone-cells with larger lumina. Vascular system 

 consists of numerous bundles which are scattered in the ground tissue 

 and are roughly arranged in rings. Bundles get smaller towards the 

 periphery. The ground tissue is formed of cells with walls thin and 

 lignified. The central portion of the ground tissue enclosed by the 

 innermost ring of bundles consists of very thin-walled cells. 



CQMMELINACEAE. 



Commelina albescens Eassk. — Pigs. 296, 297. Epidermal 

 cells of the leaf tabular, thin-walled and with outer walls flat. 

 Stomata on both the surfaces and accompanied by subsidiary cells. 

 Mesophyll of palisade tissue on the upper side and of arm-palisade 

 tissue on the lower. Internal glands in the form of cells with 

 tanniniferous contents. Bundles of acicular raphides in lower 

 epidermal cells. Clothing hairs on the leaf in the form of uniseriate 

 bracket-shaped trichomes. Pericycle forming a composite ring of 

 stone-cells. Collenchyma subepidermal. Assimilatory tissue lacunar 

 Vascular bundles apposed to the stone-tissue of pericycle. Numerous 

 isolated secretory receptacles surrounded by parenchyma in the ground 

 tissue. 



