PLANTS OF THE INDIAN DESERT. 103 



AMARANTACEAE. 



Aerua tomentosa Forsk.— Figs.:271, 272, 273, 274. Mesophyll 

 bifacial. Veins with bundle-sheaths. Mid-rib prominent above and 

 below. Clustered crystals in the leaf and axis. A dense covering of 

 candelabra hairs on the leaf and axis. Collenchyma in the angles of 

 the axis. Assimilatory tissue in the axis chloreuchymatous. Pericycle 

 of groups of stone-cells. Pith of thick-walled cells. 



Aerua pseudo-tomentosa Blatt. & Ball— Figs. 275, 277, 280, 

 281. Mesophyll bifacial. Clustered crystals in the leaf and axis. 

 Veins with bundle-sheaths. Mid-rib furrowed above and prominent 

 below. A dense covering of candelabra hairs on the leaf and axis. 

 Assimilatory tissue in the axis formed of palisade cells. Collenchyma 

 in the angles. Pericycle of groups of stone-cells. Pith of thick*walled 

 cells. 



Achyranthes aspera L.— Figs. 282, 283, 284. Mesophyll 

 bifacial. Clustered crystals in the leaf and axis. Veins without 

 bundle-sheaths. Clothing hairs in the form of uniseriate trichomes 

 with walls knobbed. Glandular hairs with a uniseriate long stalk 

 and with an ellipsoidal head. Collenchyma in the angles. Assimila- 

 tory tissue in the axis chlorenchymatous. Pericycle of groups of 

 stone-cells and isobilateral. Two vascular bundles in pith. Pith of 

 thin-walled cells. 



Pupalia lappacea Moq.— Figs. 276, 278, 279. Mesophyll bifa- 

 cial. Oxalate of lime in the form of clustered crystals in the leaf and 

 that of crystal sand in the axis. Veins without bundle-sheaths. Hairs 

 uniseriate, curved and smooth-walled. Collenchyma in angles. Assimi- 

 latory tissue in the axis chlorenchymatous. Pericycle of groups of 

 stone-cells and isobilateral. Pith of thin- walled cells. 



Structure of the Leaf. — The epidermis consists of tabular 

 cells with the outer and inner walls thickened and convexly arched 

 outwards and inwards respectively. The lateral walls are thin and 

 straight. The stomata are more numerous on the lower surface and 

 are surrounded by ordinary epidermal cells. The guard-cells of the 

 stomata on the upper surface are in the plane of surrounding cells and 

 the front cavity is placed in a depression formed by outer thickened 

 epidermal walls (fig. 275). The guard-cells of the stomata on the 

 lower surface are a little elevated and the front cavity is on a level 

 with the surface. The stomata on the axis are placed in depressions 

 formed by outer thickened epidermal walls. The stomata are replaced 

 by lenticels in the rhizomatous axes of A. tomentosa. 



The mesophyll is composed of palisade tissue on the upper and 

 of spongy tissue on the lower. Oxalate of lime occurs in the form of 



