cells found in mesophyll. Clothing hairs in the form of flagellum trie- homes. Glandular hairs biseriate and club-shaped. Collenchyma composite and sub-epidermal in the axis. Wood composite. Medul- lary rays 1-3 seriate. Medullary xylem bundles present. Pith formed of cells with thickened and lignified walls. Some of the pith cells holding dark granular contents and also rounded bodies.
Eclipta erecta L. Figs. — 178, 179. Very herbaceous. Stomata depressed. Mesophyll composed of arm-palisade cells. Clothing hairs absent. Glandular hairs depressed, biseriate and spherical. Collen- chyma sub-epidermal in the axis. Wood composite and deeply lobed on the inner side. Pith formed of thin-walled cells.
Echinops echinatus B.— Figs. 180, 181 , 182. Very herbaceous. Stomata elevated. Mesophyll formed of palisade tissue on the adaxial side and of arm-palisade tissue on the abaxial side. Clothing hairs in the form of flagellum trie homes. Glandular hairs long-stalked and with an irregularly divided spherical head. Collenchyma sub-epi- dermal in the axis. Endodermis formed of large thin-walled cells. Wood composed of large xylem bundles alternating with small ones. Pith consisting of thin-walled cells.
Volutarella divaricata Bth.— Fig. 183. Very herbaceous. Stomata elevated. Mesophyll isobilateral. Clothing hairs absent. Glandular hairs long-stalked and with a head irregularly divided. Collenchyma sub-epidermal in the axis. Wood more or less composite. Pith formed of thin-walled cells.
Dicoma tomentosa Cass.— Figs. 184, 185, 186, 187, 188, 189. Herbaceous. Stomata depressed. Mesophyll composed of palisade tissue on the upper side and of arm-palisade tissue on the lower. Clothing hairs in the form of uniseriate flagellum trichomes. Glan- dular hairs depressed, uniseriate and spherical. Collenchyma strength- ening the ribs of the axis. Wood not composite. Pith consisting of thin-walled cells.
Launaea chondrilloides II. f — Figs. 190. Herbaceous. Stomata depressed on the leaf but elevated on the axis. Mesophyll formed of arm-palisade cells. Clothing and glandular hairs absent. Collenchyma not developed in cortex. Wood not composite. Assimilatory tissue in the axis formed of palisade tissue. Pith formed of thin-walled cells.
Structure of the Leaf: — The epidermal cells are alike on both the sides and have the outer walls greatly thickened and convexly arched outwards. The lateral walls are thin and undulated; inner walls are usually thickened. The cells at the margin are rounded and have outer walls toothed in D. tomentosa and papillose in other members.
