Page:The Journal of Indian Botany.djvu/497

 ferent portions of the axis which are not equally affected by the sun and wind. The pith consists of thin-walled cells or of cells with thickened and lignified walls.

SOLANAGEAE.

Solanum incanum L. — Figs. 241, 242, 243, 244. Mesophyll bifacial. Oxalate of lime found in the form of crystal sand in mesophyll, cortex, soft-bast, intraxylary phloem and pith. Clothing hairs tufted. Epidermis one layered. Cork subepidermal. Collenchyma developed below cork. Pericycle forming a loose ring of bast fibres. Vessels arranged in bundles connected by strands of interfascicular wood prosenchyma.

Solanum albicaule Kotsc — Figs. 236, 237, 238. Mesophyll isobilateral. Oxalate of lime found in the form of crystal sand in mesophyll and pith. Clothing hairs tufted and uniseriate trichomes. Epidermis of the axis three layered. Collenchyma subepidermal. Vessels few and uniformly distributed in the wood-ring. Intraxylary phloem present.

Lycium barbarum L.— Fig. 239. Mesophyll isobilateral. Oxal- ate of lime found in the form of crystal sand in mesophyll of the leaf and epidermis s soft bast and pith of the axis. Clothing hairs absent. Epidermis of the axis one-layered and with outer walls thickened and muriculate. Sclerenchymatous pericycle not developed. Cork subepidermal and characterised by isolated stone-cells. Vessels few and uniformly distributed in the wood-ring. Intraxylary phloem present-

Structure of the Leaf : — The epidermal cells are tabular with the outer walls thickened and convexly arched outwards. The lateral walls are thin and undulated. The outer walls in L. barbarum (fig. 239) are muriculate. The upper epidermal cells are mostly filled with crystal sand.

The stomata are equally numerous on both the surfaces of isobi- lateral leaves, while they are more numerous on the lower surface of bifacial leaves. The front cavity is placed in a depression formed by outer thickened epidermal walls. The guard-cells are accompanied by ordinary epidermal cells.

The mesophyll is isobilateral in S. albicaule and L. barbarum and is bifacial in S. incanum. Some of the palisade cells contain crystal sand.

Oxalate of lime occurs in the form of crystal sand in all members. Cells filled with crystal sand are found abundantly in the mesophyll of the leaf and in the epidermis of the axis of L. barbarum ,