Page:The Journal of Indian Botany.djvu/139

 anti-chorus and C. tridens and 1-3 seriate in G. abutilifolia. Wood parenchyma is poorly developed.

The wood in G. trilocularis is narrowed on one side, the narrowed portion being characterised by a larger number of vessels and the broader portion by more extensive wood prosenchyma. These modifications in the structure of the wood may be the result of the inclined nature of the axis, the narrowed portion being situated on the lower side of the inclined axis. The abundance of wood pro- senchyma on the upper side prevents the axis from bending.

The pith is composed of thin-walled cells in species of Corchorus and of thick-walled cells in species of Grewia.

General Review : — There are a number of characters which can be used for the diagnosis of the two genera.

Corchorus : — Stomata with smaller epidermal cells on either side of the guard-cells. Oxalate of lime in the form of clustered crystals near the veins. Veins embedded and not provided with bundle-sheaths. Clothing hairs unicellular. Outer walls of epider- mal cells of the axis greatly thickened and cuticularised. Cortex composed of three zones — outermost parenchyma, middle collenchyma and innermost parenchyma. Pith composed of thin-walled cells.

Grewia : — Stomata with ordinary epidermal cells on either side of the guard-cells. Oxalate of lime in the form of solitary crystals. Veins vertically transcurrent and provided with green bundle-sheaths. Clothing hairs usually tufted. Epidermal cells of the axis uniformly thickened on all sides. Cortex composed of three zones — outermost cork, middle collenchyma, innermost parenchyma. Pith formed of thick-walled cells. {{c|{To be continued.)}}