Page:The Journal of Indian Botany.djvu/597

 THE

journal of India

Vol. II. JULY, 1921. Nos. 6 & 7.

THE PHYSIOLOGICAL ANATOMY OF THE PLANTS OF THE INDIAN DESERT

BY LIBRAE

T. S. Sabnis, B.A., M.Sc. new ,

(Continued from p. 107).

Salsola foetida Del— Figs. 287, 289, 290. Leaf suborbicular and fleshy. Stomata depressed. Aqueous tissue subepidermal. Pali- sade tissue forming a continuous ring. Clustered crystals in subepi- dermal and central aqueous tissue. Veins peripheral and central. Central veins embedded in a cylinder of stone-cells. ColJenchyma below epidermis of the axis. Cortical parenchyma forming an aqueous tissue. Pericycle of small isolated groups of stone-cells. Vascular bundles in the axis embedded in interfascicular wood prosenchyma and forming a hollow cylinder. Pith of thin- walled large cells.

Structure of the Leaf— Epidermal cells in S. foetida have outer walls papillose and they are of two sizes, larger ones bearing hairs. Epidermal cells in H. recurvum have outer walls convexly arched outwards. Outer walls are not much thickened in any of the members. The guard-cells are usually placed in the plane of surrounding cells, though in H. recurvum they are sometimes distinctly situated below the plane of epidermal cells. Stomata are surrounded by ordi- nary epidermal cells and the front cavity is closed by outer horns of the guard-cells.

Mesophyll is differentiated into assimilatory and aqueous tissue. The assimilatory tissue in S. foetida consists of a continuous ring of palisade cells. Palisade cells in H. recurvum form a continuous layer,
 * — broken at the angles, in portions of the leaf towards the apex ; but as we proceed examining sections from the apex to the base of the leaf " the palisade tissue is seen to disappear also at the middle of the flat