Page:The Journal of Indian Botany.djvu/606

166 THE JOURNAL OF INDIAN BOTANY. veins apposed to the stereome girders except a few very small ones. A few larger veins vertically transcurrent above and below by stereome. Bundle-sheaths, when present, internal. Mechanical tissue in the leaf in the form of isolated subepidermal girders below the veins, and of a few isolated girders on the upper side placed at regular intervals. T. S. of the axis triangular. Assimilatory tissue in the axis forming arcs or girders of palisade cells round the peripheral bundles. Mechanical tissue in the axis in the form of isolated sub-epidermal girders, larger ones alternating with the smaller. Ground tissue not differentiated in the centre into pith.

Cypems arenarius Retz. — Margins bluntly pointed without any supporting stereome bundles. Stomata only on the lower surface and with the front cavity depressed. Obconical groups of elongated cells occurring below the epidermis even in the absence of stomata. Veins embedded. Smaller veins near the lower epidermis. Bundle- sheaths, when present in leaf or axis, internal. Mechanical tissue in the form of isolated sub-epidermal girders below smaller veins. T. S. of the axis circular. Assimilatory tissue in the axis forming arcs or girders of palisade cells round peripheral bundles. Mechanical tissue in the axis forming numerous isolated girders, larger ones alterna- ting with the smaller. Ground tissue not differentiated in the centre into pith.

Cyperus conglomeratus Rottb.— Figs. 300, 301, 302. Mar- gins bluntly pointed and supported by stereome bundles. Extensive articulation tissue on the upper side. Stomata only on the lower surface. Front cavity depressed. Obconical groups of elongated cells occurring below the epidermis even in the absence of stomata. Bundle-sheaths, when present, internal. Veins embedded and ar- ranged in an alternating fashion in two rows. Smaller veins nearer the lower epidermis. Mechanical tissue in the leaf in the form of isolated sub-epidermal girders below all smaller veins and of a single long sub-epidermal girder on the upper surface near the margin. T. S. of the axis circular. Assimilatory tissue, in the axis forming arcs or girders of palisade cells round the peripheral vascular bundles. Mechanical tissue of sub-epidermal girders, alternating with the peri- pheral bandies and apposed to the girders. A few vessels enclosed in a thick ring of stereome in the ground tissue. Ground tissue differ- entiated in the centre into pith.

Cyperus rotundus L — Figs. 303, 304, 305, 306, 307. Margins rounded and without supporting stereome bundles. Upper epidermis modified into articulation tissue. All veins embedded. Larger veins nearer the lower epidermis and the smaller ones in the middle of the