Clothing hairs unicellular and conical. Glandular hairs formed of a stalk-cell and of a spherical head divided by horizontal and vertical walls. Crystal sand in the clothing hairs of the leaf and in epidermal cells of the axis. Collenchyma forming a continuous ring. Aqueous tissue occurring below collenchyma. Pericycle in the form of isolated bast fibres. Vessels uniformly distributed in the wood-ring. Inter-fasciculer wood prosenchyma fairly extensive. Wood parenchyma fairly extensive- Medullary rays few and uniseriate. Pith of thin- walled cells.
Ruellia patula J acq.— Fig. 251. Guard-cells elevated. Front cavity on a level with the surface. Mesophyll of palisade tissue on the upper side and of arm-palisade tissue on the lower. Veins not provided with bundle-sheaths. Clothing hairs uniseriate and more or less jointed. Glandular hairs with an uniseriate stalk and with a disc-shaped head divided by horizontal and vertical walls. Assimilatory tissue in the axis parenchymatous. Structures resembling internal glands found in cortex. Pericycle of a few isolated bast fibres. Wood composed of large bundles at the angles and connected by strands of interfascicular wood prosenchyma. Wood parenchyma in groups on the inner side of xylem bundles. Medullary rays uniseriate. Pith of thick-walled cells.
Barleria hochstetteri Nees — Figs. 252, 253, 254, 255, 256, 257. Guard-cells in the plane of surrounding cells. Mesophyll isobilateral. Veins without bundle-sheaths. Structures resembling internal glands present. Clothing hairs on the leaf short and unicellular, and those on the axis in the form of armed trichomes. Glandular hairs with an uniseriate stalk and with a disc-shaped head divided by a vertical wall. Collenchyma strengthening the ribs. Assimilatory tissue in the axis parenchymatous. Sclerenchymatous pericycle not developed. Vessels uniformly distributed in the wood-ring. Wood narrowed at two opposite points. Medullary rays uniseriate. Interfascicular wood prosenchyma little developed. Pith of thin-walled cells and retained. Pith cells with acicular or rod-like crystals. A thick-walled vessel present in pith.
Justicia simplex Don.— Fig. 258, 259. Guard-cells elevated or in the plane of surrounding cells. Mesophyll isobilateral. Structures resembling internal glands found in the mesophyll. Veins without sheaths. Clothing hairs short and uniseriate. Glandular hairs with a stalk-cell and with a spherical head divided by horizontal and vertical walls. Assimilatory tissue in the axis formed of palisade cells. Collen- chyma developed at the angles of the quadrangular axis. Scleren- chymatous pericycle not developed. Wood composed of xylem bundles at the angles connected by strands of interfascicular wood pro-
