108 THE JOURNAL OF INDIAN BOTANY. 



pith. Solitary crystals are sometimes found in groups of 3-4 in the 

 cells ; they are sometimes also aggregated in the form of conglomerate 

 crystals in the axis of species of Grcwia. 



The veins are embedded and are not provided with bundle- 

 sheaths in species of Gor chorus. The veins are vertically transcurrent 

 above and below by sclerenchyma in Grcwia poimlifolia and Grcwia 

 abutilifolia and above by sclerenchyma and below by sheath cells in 

 Grewia villosa. The veins in species of Grcwia are provided with 

 bundle-sheaths. In Grcwia abutilifolia there are structures of the 

 nature of water-storing tracheids at the terminations of the veins. 



Hairy covering on the leaf and axis consists of clothing and 

 glandular hairs. The clothing hairs in species of Corchorus are 

 unicellular, thick- walled and not dense (fig. 6G). In Grcwia they are 

 tufted (figs. 63, 64), the constituent rays being unicellular and thick- 

 walled. Besides the tufted hairs, there are unicellular thick-walled 

 hairs, resembling the rays of the tufted hairs, on the axis of Grewia 

 abutilifolia (fig. 63). The glandular hairs are club-shaped and are 

 composed of a stalk-cell and of a head divided only by horizontal wall3 

 (figs. 65, 63), or by both horizontal and vertical walls (tig. 64). 



Structure of the Axis : — The epidermis in species of Corchorus 

 consists of horizontally tabular ceils with outer walls thickened and 

 arched convexly outwards, the thickening: of the outer walls being 

 quite considerable in Corchorus trilocularis and Corchorus tridens. 

 The lateral and inner walls are also thickened. The epidermal cells 

 in species of Grcwia are horizontally tabular and are uniformly 

 thickened on all sides. The lateral walls are straight in members of 

 both the genera. 



The cortex is characterised by subepidermal cork in species of 

 Grcwia, the innermost layers of which in G. villosa are composed of 

 thickened and lignified cork-cells. Cork does not occur in species of 

 Corchorus. Three tissues may be distinguished in the cortex : in 

 species of Corchorus outermost parenchyma, middle collenchyma 

 and innermost parenchyma ; in species of Grewia outermost cork, 

 middle collenchyma and innermost parenchyma. 



Internal secretory organs are represented in the axis of members 

 of both the genera by mucilage cavities in the cortical parenchyma 

 (figs. 67, 64) and in the pith (fig. 64). 



The pericycle is composed of closely placed groups of stone-cells 

 with very small lumina (figs. 64, 67). The wood forms a composite 

 hollow cylinder. The vessels are arranged in rows. The interfascicular 

 wood prosenchyma is extensive and is composed of cells with wide 

 lumina. The medullary rays are numerous ; they are uniseriate in 

 Q. trilocularis, G. vopulifolia and G. villosa, 1-2 seriate in C. 



