Page:The Journal of Indian Botany.djvu/286

 Anomolous structures are represented by cortical vascular bund- les in C. Burhia, fig. 101.

Outer walls of the epidermal cells are thickened and cuticuiarised. Spongy tissue is greatly diminished and the ventilating system is greatly reduced. Water-storing tissue is extensive in the leaf and occurs either in the epidermis or in the palisade tissue, or in the middle of the mesophyll. Tannin sacs are abundant. Secretory cavities are represented by intramural glands in Psoralen odorata. Oxalate of lime is not found in the leaf or axis. The system of veins is poorly developed. Clothing hairs are never unicellular ; they are uniseriate trichomes, either simple, or hooked, or armed. Glandular hairs are either club-shaped or spherial and are not abundant.

The pericyle forms a composite ring either of groups of bast fibres or of stone-cells. Vessels have simple perforations and are not numer- ous. Inter fascicular wood prosenchyma is abundantly developed forming the ground work of the vessels. Wood parenchyma is poorly developed. Medullary rays are usually uniseriate and numerous.

The pith consists of thin-walled or thick-walled and lignified cells.

Anomelous structures are represented by cortical vascular bundles in 0. burhia.

Cassia obovata, Goliad.— Figs 118,119. Epidermal cells with outer walls papillose. Stomata occurring on both the surfaces. Mesophyll isobilateral. Veins embedded. Clothing hairs unicellular. Assimilatory tissue formed of chlorenchyma. Vessels large. Medullary rays uniseriate. Pith formed of cells with thickened and lignified walls.

Structure of the Leaf : — The epidermal cells have outer walls drawn out into large papillage, fig. 118. The stomata are equally numerous on both the surfaces. Guard-cells are situated in the plane of surrounding cells ; and the front cavity is placed in a deep depres- sion formed by the outer papillose epidermal walls.

The mesophyll is isobilateral. The palisade tissue on the adaxial side consists of longer cells than those on the lower surface with transversely elongated cells between. The veins are embedded. The large veins are protected above and below by sclerenchyma ; the smaller ones have large strands of sclerenchyma only on the lower side.