PLANTS OF THE INDIAN DESEKT. 67 



walls of the epidermal cells in Cleome papillosa (fig. 11), Cadaba 

 indica (figs. 30, 31) and Capparis decidua, the guard-cells being 

 situated in the plane of the surrounding cells. In the other mem- 

 bers the guard-cells are elevated above the plane of the surrounding 

 cells, so that the front cavity is on a level with the surface 

 (figs. 23, 27.). 



The mesophyll is composed of palisade tissue on the adaxial 

 side in all the members and on the abaxial side of arm-palisade 

 tissue in Cleome viscosa (fig. 16) or of spongy tissue in Gynandropsis 

 pentaphtjlla (fig. 22). The mesophyll is isobilateral and is composed 

 wholly of short palisade cells in Cadaba indica (fig. 30) or com- 

 posed of palisade tissue on either side with a middle tissue of 

 thin-walled colourless parenchymatous cells in Cleome brachycarpa 

 (fig. 14) and Capparis decidua. The middle tissue in the former 

 partakes in the formation of bundle-sheaths ; and in the latter it is 

 very extensive and forms perhaps a water-storage tissue. Internal 

 secretory organs are of the nature of myrosin cells and are repre- 

 sented by (a) palisade like cells occurring in small groups on both 

 sides below the epidermis in Cleome viscosa or (b) by parenchymatous 

 cells in the middle tissue in Cadaba indica (fig. 30) and in Capparis 

 decidua commonly occurring near the veins and quite numerous 

 above the bundle of the mid-rib. The veins are embedded in all the 

 members. They are provided with a sheath either of large colour- 

 less parenchymatous cells or of distinct green parenchymatous cells 

 in Cleome brachycarpa (fig. 14) and Gynandropsis pentaphylla 

 (fig. 22) respectively. Groups of large water-storing tracheids occur 

 at the terminations of the veins in Cadaba indica (fig. o0 W). The 

 vascular bundles of the mid-rib are arranged in the form of an arc 

 with collenchyma on the lower side extending to the epidermis. The 

 mid-rib projects on the lower side. 



The hairy covering of the leaf and axis consists of (a) clothing 

 and (b) glandular hairs. 



(a) Clothing hairs are not unicellular in any of the members. 

 Cleome papillosa and Cleome brachycarpa have shaggy hairs, the cells 

 of which end superficially in sharp spiny apices (figs, 10, 11, 12). 

 In Cadaba indica there are peltate hairs composed of a uniseriate 

 stalk, much longer on the axis, and of a circular shield which in 

 surface view presents a notched margin (fig, 33). Hairs are more 

 numerous on the lower side of the leaf and especially on the mid-rib. 



(b) Glandular hairs are present on the leaf and axis in all 

 members except Cadaba indica. They are composed of a multicellu- 

 lar head irregularly divided (figs. 11, 13,.* 18). They are not 

 numerous either on the leaf or axis ; they are however more common 



