Page:The Journal of Indian Botany.djvu/689

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 unequally 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. Assimilatory 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-girders. 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.