Page:The Journal of Indian Botany.djvu/93

Rh 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 members 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 pentaphtylla (fig. 22). The mesophyll is isobilateral and is composed wholly of short palisade cells in Cadaba indica (fig. 30) or composed 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 represented 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 colourless 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. 30 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 multicellular head irregularly divided (figs. 11, 13, 18). They are not numerous either on the leaf or axis; they are however more common