PLANTS OF THE INDIAN DESERT. 223 



numerous on the upper surface. Articulation tissue extending be- 

 tween two surfaces. Veins few, embedded and with complete sheaths. 

 Palisade cells forming complete girders. Mechanical tissue forming 

 I-girders in association with all the veins. Mechanical tissue in 

 the axis forming stereome tube supplimented by I-girders. Webs 

 formed by mixed vascular bundles. Assimilatory tissue in the axis 

 formed of palisade cells and with a continuous layer of sheath cells on 

 its inner side. Smaller vascular bundles forming webs of I-girders. 

 Larger vascular bundles in the medullary tissue. Medullary tissue of 

 thin- walled cells. 



Panicum antidotale Betz.—Eig. 322. Leaf deeply but un- 

 equally grooved on two surfaces. Hairs spiny and absent on the 

 axis. Stomata more numerous on the lower surface. Rows of articul- 

 ation tissue cells not as conspicuous as in P. turcjiclum. Veins 

 numerous. Palisade cells forming complete girders round the veins. 

 Mechanical tissue in the form of I-girders in association with larger 

 veins. Veins embedded and provided with complete sheaths. Assi- 

 milatory tissue in the axis formed of chlorenchyma. Mechanical 

 tissue in the axis formed by stereome tube supplemented by sub- 

 epidermal I-girders. Webs formed by unmixed vascular bundles. Some 

 of the smaller vascular bundles embedded in the assimilatory tissue. 

 Smaller vascular bundles provided with arcs or complete girders of 

 sheath-cells. Some of the larger bundles embedded in the stereome 

 tube. Larger bundles numerous in the medullary tissue Medullary 

 tissue of thin-walled cells. 



Cenchrus catharticus Del.— Figs. 323, 324. Leaves deeply 

 grooved on the upper surface. Epidermal cells vertically elongated. 

 Margins blunt and with large stereome bundles. Stomata more 

 numerous on the lower surface. Hairs spiny and absent on the axis. 

 Articulation tissue extending between two surfaces. Veins provided 

 with complete sheaths. Larger veins vertically transcurrent above 

 and below by aqueous cells and sub-epidermal stereome girders. Larger 

 veins placed in a higher plane and situated below the ridges. 

 Mechanical tissue in the leaf in the form of isolated sub-epidermal 

 girders on the lower side of the veins in furrows and on both the 

 sides of the veins in the ridges forming I-girders. Webs formed by 

 mixed bundles. T. S. of the axis horn-shaped. Assimilatory tissue 

 forming strands of chlorenchyma between smaller bundles. Mechani- 

 cal tissue in the axis forming a stereome tube supplimented by I-gir- 

 ders. Webs formed by unmixed small bundles. Smaller bundles 

 forming webs of I-girders. Of the larger bundles some embedded in 

 the stereome tube and some in the medullary tissue. Medullary tissue 

 of thin-walled cells. 



