Page:The Journal of Indian Botany.djvu/137

 the veins and in the cortex. Veins vertically transcurrent above and below by sclerenchyma with water-storage tracheid-like structures at their terminations. Clothing hairs tufted and unicellular. Glandular hairs club-shaped with the head divided by horizontal and vertical walls. Pericycle of stone-cells and not composite. Medullary rays 1-3 seriate.

Corchorus trilocularis L.— Fig. 65. Clustered crystals near the veins and few. Glandular hairs club-shaped with the head divided by horizontal and vertical walls. Clothing hairs unicellular* Epidermis of the axis with outer walls considerably thickened and cuticularised. Lateral walls thickened. Wood narrowed on the lower portion of the inclined axis. Medullary rays uniseriate.

Corchorus antichorus Baens.— Clustered crystals near the veins and few. Clothing hairs unicellular. Glandular hairs club- shaped with the head divided by horizontal and vertical walls. Epi- dermis of the axis with the outer walls greatly thickened and cuticularised. Lateral and inner walls also a little thickened. Medull- ary rays 1-2 seriate. ■

Corchorus tridens L.— Figs. 66, 67. Clustered crystals near the veins and numerous. Clothing hairs unicellular. Glandular hairs club-shaped and with the head divided by horizontal walls* Epidermis of the axis with outer walls greatly thickened and with lateral and inner walls also a little thickened. Medullary rays 1-2 seriate.

Structure of the Leaf : — The epidermis of the upper side con- sists of almost cubical cells and of the lower side of horizontally tabular cells. The outer walls are a little thickened ; the inner and lateral walls are thin. The lateral walls are straight. Epidermal C8lls surrounding the sfcomata are usually much smaller and are of the nature of subsidiary cells.

The stomata are more numerous on the lower surface, while in species of Greiuia they occur only on the lower surface. The guard- cells are elevated and the front cavity is on a level with the surface. In species of Corchorus epidermal cells on either side of the guard- cells are elevated and are much smaller than the ordinary epidermal cells ; they seem to be of the nature of subsidiary-cells. The stomata on the axis are like those on the leaf.

The mesophyll is composed of palisade tissue on the upper side and of arm-palisade tissue on the lower.

Oxalate of lime occurs in the form of numerous clustered crystals near the veins in species of Corchorus (fig. 66). In species of Greivia solitary crystals are found near the veins (fig. 63), and in the cortex and