The Journal of Indian Botany/Volume 2/August 1921/The Physiological Anatomy of the Plants of The Indian Desert

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4465003The Journal of Indian Botany Volume 2 August 1921 — The Physiological Anatomy of the Plants of The Indian Desert
By T. S. Sabnis
1921

THE

journal of India

Vol. II. JULY, 1921. Nos. 6 & 7.

THE PHYSIOLOGICAL ANATOMY OF THE PLANTS OF THE INDIAN DESERT

BY LIBRAE

T. S. Sabnis, B.A., M.Sc. new ,

(Continued from p. 107).

CHENOPODIACEAE.— (Contd.)

Salsola foetida Del— Figs. 287, 289, 290. Leaf suborbicular and fleshy. Stomata depressed. Aqueous tissue subepidermal. Pali- sade tissue forming a continuous ring. Clustered crystals in subepi- dermal and central aqueous tissue. Veins peripheral and central. Central veins embedded in a cylinder of stone-cells. ColJenchyma below epidermis of the axis. Cortical parenchyma forming an aqueous tissue. Pericycle of small isolated groups of stone-cells. Vascular bundles in the axis embedded in interfascicular wood prosenchyma and forming a hollow cylinder. Pith of thin- walled large cells.

Structure of the Leaf— Epidermal cells in S. foetida have outer walls papillose and they are of two sizes, larger ones bearing hairs. Epidermal cells in H. recurvum have outer walls convexly arched outwards. Outer walls are not much thickened in any of the members. The guard-cells are usually placed in the plane of surrounding cells, though in H. recurvum they are sometimes distinctly situated below the plane of epidermal cells. Stomata are surrounded by ordi- nary epidermal cells and the front cavity is closed by outer horns of the guard-cells.

Mesophyll is differentiated into assimilatory and aqueous tissue. The assimilatory tissue in S. foetida consists of a continuous ring of palisade cells. Palisade cells in H. recurvum form a continuous layer,

  • — broken at the angles, in portions of the leaf towards the apex ; but as we proceed examining sections from the apex to the base of the leaf " the palisade tissue is seen to disappear also at the middle of the flat and arched surfaces of the leaf. In sections of the basal portion,

the palisade tissue disappears all along the flat surface. Gaps in the palisade tissue are filled in by palisade-like aqueous cells along the flat surface and by polygonal aqueous cells at the angles and along the middle portion of the arched surface. Some of the polygonal aqueous cells at the angles contain large clustered crystals.

The aqueous tissue consists partly of a I continuous layer of subepidermal aqueous cells many of which contain clustered crystals, and chiefly of a centrally placed mass of large aqueous cells which enclose the central veins as well as the smaller ones lying at the periphery of the aqueous tissue. The centrally placed aqueous tissue is bounded by a layer of cubical or tabular cells in those parts where the palisade tissue is present in S. foetida and H. recurvum respect- ively. Cells of this layer contain chlorophyll and resemble cells of bundle-sheaths. This layer may assist the assimilatory tissue in carbon assimilation as well as serve to bring into contact the assimilatory and vascular tissue. Some of the peripheral cells of the central aqueous tissue contain clustered crystals in the neighbourhood of the veins.

Oxalate of lime is found in the form of clustered crystals which are found in subepidermal aqueous cells as well as in aqueous cells of the central tissue in the neighbourhood of peripheral veins. Internal glands are not found in the leaf and axis of any members.

The system of veins consists of centrally placed veins, of veins traversing the central aqueous tissue and of peripheral veins situated beneath the sheath-layer which forms a bundle-sheath common to all the veins and which brings into contact the assimilatory and vascular tissues. The central vein in S. foetida is embedded in a cylinder of stone-cells, while that in H. recurvum is surrounded by a tissue of small thin-walled parenchymatous cells.

Hairy covering on the leaf and axis of S. foetida consists of uniseriate trichomes seated on larger epidermal cells. Hairs are composed of a, basal portion of a few short cells and of an irregularly curved and pointed terminal portion which consists of longer cells with walls covered with solid papillae (fig. 287). Hairs are not found in both the species of Haloxylon. External glands do not occur in any of the members.

Structure of the Axis. — Epidermal cells in H. recurvum have outer walls thickened and papillose; those in H. salicornicum are tabular and thin-walled and those in S. foetida are small polygonal cells with outer walls thickened and granulated. Stomata have the same characters as those on the leaf. Primary cortex is characterised by a sub-epidermal continuous layer of collenchyma in S. foetida, by assimilatory tissue of palisade cells in both the species of Haloxylon and by the occurrence of an aqueous tissue in all the members. Collenchyma possesses chlorophyll and may function as an assimilatory tissue in S. foetida. Palisade cells form a continuous ring in H. salicornicum, while in H. recurvum the continuity of the palisade tissue is broken by groups of colourless palisade-like cells with perhaps a water-storing function.

The aqueous tissue is extensive in species of Haloxylon and it consists of a sub-epidermal layer of tabular aqueous cells and of a centrally placed tissue of polygonal cells surrounding the central vascular cylinder. The central aqueous tissue is bounded by a layer of cubical cells containing chlorophyll and resembling bundle-sheath cells ; and it is traversed by vascular bundles. The aqueous tissue in S. foetida is represented by a tissue of polygonal cells below collenchyma and it is not extensive.

In H. recurvum (fig. 288) there is cork developed just outside the ring of soft bast and it seems to be of pericyclic origin. It may have been developed to protect the poorly developed central vascular cylinder from desiccation. Pericycle consists of groups of stone-cells. Stone-cell groups in S. foetida are very small and isolated. Stone-cell groups in H. salicornicum are rhomboidal and present an isobilateral arrangement, the larger ones being developed in the plane most affected by the prevailing wind. In H. recurvum it presents a peculiar arrangement. It is composed of long broad and composite strands in the plane of gaps in the palisade tissue and of thin narrow strands or isolated stone-cells in other parts of the pericycle. The occurrence of stronger strands is perhaps necessary in the plane of gaps as the aqueous tissue in this plane is more extensive.

The vascular system is represented by peripheral bundles below the sheath-cells, by bundles traversing the aqueous tissue and by centrally placed bundles in species of Haloxylon ; in S. foetida it consists only of centrally placed bundles. Vascular bundles in the central cylinder are embedded in interfascicular wood prosenchyma of thick- walled cells in a concentric fashion, the largest ones being situated towards the pith. Vessels are small and have simple perforations. Medullary rays are not found.

In addition to a continuous peripheral thin ring of soft bast there are groups of soft bast on the outer side of the bundles, embedded in interfascicular wood prosenchyma.

Pith consists of thick-walled cells in.lH. recurvum; in other members it consists of thin-walled cells.

Oxalate of lime is found in the form of clustered crystals in some of the cells of the aqueous tissue of all the members. Besides the clustered crystals in the "aqueous tissue, there is a continuous layer of rounded thin-walled cells, most of which contain clustered crystals ; it is situated beneath the sub-epidermal aqueous tissue in H. salicornicum. It may be termed a crystal layer.

General Review. — Epidermal cells have outer walls thin and more or less papillose. Stomata are depressed and guard-cells are situated in the plane of surrounding cells. The assimilatory tissue in the leaf and axis consists of palisade cells. The leaf and axis are characterised by the extensive development of an aqueous tissue, either peripheral, or central or both. The vascular system in the leaf consists of peripheral and central veins ; and it is brought into contact with the assimilatory tissue by means of sheath-cells. Hairy covering, when present, consists of uniseriate trichomes densely covered with solid papillae. Oxalate of lime occurs in the form of clustered crystals in the leaf and axis.

Sclerenchymatous pericycle is found in all the members. The vascular system in the axis consists of bundles traversing the aqueous tissue as found in species of Haloxylon and of a central cylinder as found in all the members. Bundles in the central cylinder are embedded in interfascicular wood prosenchyma in a concentric fashion. Vessels are small and have simple perforations. Medullary rays are not found in any of the members.

POLYGONACEAE.

Calligonum polygonoides L— Figs. 291, 292, Woody. Mesophyll isobilateral with a middle layer of cells with tanniniferous contents. Palisade-like cells with tanniniferous contents in the palisade tissue. Clothing hairs in the form of uniseriate trichomes. External glands club-shaped. Epidermal cells of the axis with outer walls very greatly thickened. Subepidermal groups of sclerenchyma present. Clustered crystals in the primary cortex. Pericycle of small groups of stone-cells. Wood composite. Interfascicular wood prosenchyma extensive. Meduallary rays 1-2 seriate and numerous. Pith of thick- walled cells.

Polygonum plebejum Br.— Wig. 293. Woody. Large water- storing cells intercalated amongst epidermal cells. Mesophyll of pali- sade tissue on the upper side and of arm-palisade tissue on the lower. Clustered crystal in the mesophyll. Bundle-sheath cells with tannini- ferous contents.

Epidermal cells of the axis with outer walls granulated. Collen- chyma groups subspidermal. Wood composed of xylem bundles. Pith of thin-walled cells. Structure of the Leaf. — Epidermal cells are polygonal with outer walls thickened and papillose on both the sides in C. polygonoides and on the upper only in 1 P. plebejum. Epidermal cells on the upper side in the latter are tabular with outer walls thickened and flat. Large water-storing cells are intercalated amongst ordinary epidermal cells in P. plebejum. Lateral walls are thin and undulated.

Stomata are surrounded by ordinary epidermal cells and are equally numerous on both the surfaces. Guard-cells are in the plane of surrounding cells and the front cavity is placed in a depression formed either by outer thickened epidermal walls or by the papillae.

Mesophyll is isobilateral in G. polygonoides, while in P. plebejum it consists of palisade tissue on the upper side and of arm-palisade on the lower. There is a tissue of polygonal cells with tanniniferous contents in the middle of the mesophyll in G. polygonoides.

Internal secretory organs are represented in G. polygonoides by polygonal cells in the middle of the mesophyll and by palisade-like cells, in the palisade tissue, with tanninifarous contents. Sheath- cells in P. plebejum hold tanniniferous contents. Oxalate of lime occurs in the form of clustered crystals in the mesophyll of P. plebejum.

Veins are embedded and are enclosed in bundle-sheaths. Sheath-cells in P. plebejum hold tanniniferous contents.

Hairy covering, in G. polygonoides, consists of uniseriate trie- homes which are composed of a basal cell and of a terminal cell with verrucose walls and more or less adpressed. External glands in C. polygonoides are club-shaped and consist of a biseriate short stalk and of a head irregularly divided.

Structure of the Axis. — The epidermis consists of small polygonal cells with outer walls thickened and papillose, thickening being considerable in G. polygonoides. Outer walls are granulated in P. plebeium. Lateral walls are thin and undulated. Some of the epidermal cells in C. polygonoides hold tanniniferous contents. The primary cortex is characterised by an assimilatory tissue of palisade cells. The mechanical tissue is represented by sub-epidermal strands of collen- chyma and of stone-cells in the ribs of P. plebejum and C. polygonoid- es respectively. Along almost one-third of the circumference of the axis, cork is developed below epidermis. This suggests that the axis is greatly inclined and that cork is developed on the upper side which is exposed to the sun. Endodermis is differentiated and is characterised by tanniniferous contents in the species of both the genera. The pericycle is composed of small groups of stone -cells (figs. 292, 293). Stone-cell groups in C. polygonoides are radially much elongated. Cells interposed between stone-cell groups are parenchymatous and hold tanniniferous contents in both the mem- bers.

Wood forms of a composite hollow cylinder in G. polygonoides, while in P. plebejum it consists of xylem bundles connected by strands of interfascicular wood prosenchyma. Vessels in G. polygonoides are small and few; they are uniformly distributed in extensive interfasci- cular wood prosenchyma formed of small cells with thick walls and with small lumina. Medullary rays are present only in C. polygonoi- des and are 1-2 seriate. Vessels in the xylem bundles of P. plebejum are many and large and the connecting strands of interfascicular wood prosenchyma are formed of cells with thin walls and with large lumina. Wood parenchyma is little developed.

Pith consists of thin-walled and thick-walled cells in P. plebejum and G. polygonoides respectively.

Oxalate of lime is found in the form of clustered crystals in the assimilatory tissue and in cortical parenchyma near the pericycle. Secretory cells with tanniniferous contents occur in the epidermis, cortical parenchyma and pith in species of both the genera, Tannin is also found in the medullary ray-cells of G. polygonoides.

The mechanical tissue consists of sub-epidermal strands and of pericyclic stone-cell groups. Sub-epidermal strands are collenchy- matous in P. plebejum, while those in G. polygonoides are formed of stone-cells. Sub-epidermal strands and the pericyclic stone cell groups together form a system of I-girders, the webs being formed by the assimilatory tissue. The occurrence of the mechanical tissue in the form of I-girders in the periphery of the axis forms a suitable strengthening tissue in the axis which is exposed to the strong winds of the desert.

AR1STOLOCHIACEAE.

Aristolochia bracteata Eetz. — Epidermis of tabular cells. Stomata found on both the surfaces and accompanied by ordinary cells. Mesophyll bifacial. Clothing hairs uniseriate and bracket-shaped. Veins embedded and with bundle-sheaths.

Structure of the leaf. — The epidermis consists of tabular cells with outer walls thickened and convexly arched outwards. Late- ral walls are thin and straight. Stomata are more numerous on the lower surface and are accompanied by ordinary epidermal cells. Guard- cells are in the plane of surrounding cells and the front cavity is placed in a depression formed by outer thickened epidermal walls.

Hair convering consists of a few clothing hairs which are uniseriate and bracket-shaped. They are composed of a unicellular dome-shaped pedestal seated on epidermal cells, of a neck and of a terminal cell bent like a hook. The tip of the hair is sharp and solid. External glands are not found.

Mesophyll is bifacial. Internal secretory organs and oxalate of lime are not found. Veins are embedded and are provided with green bundle-sheaths.

EUPHORBIACEAE.

Euphorbia granulata For sk.— Wig. 294. Epidermal cells of the leaf with outer walls greatly papillose. Internal glands absent in the leaf. Internal secretory cells in the axis with tanniniferous contents. Veins provided with bundle-sheaths. Clothing hairs uni- seriate trichomes with muriculate walls. Epidermis of the axis one-layered. Pericycle of isolated bast fibres. Vessels numerous. Interfascicular wood prosenchyma not extensive.

Phyllanthus niruri L.— Fig. 295. Epidermal cells of the leaf with outer walls a little papillose. Internal secretory cells with tanniniferous contents in the spongy tissue. Numerous solitary crystals in the palisade tissue, Veins without bundle-sheaths. Clothing hairs thick- walled and unicellular or septate. Epidermis of the axis two-layered. Collenchyma in the ribs of the axis. Pericycle forming a loose ring of groups of bast fibres. Vessels few. Interfascicular wood prosenchyma extensive.

Structure of the leaf. — Epidermal cells have outer walls thickened and papillose, papillae being large and conspicuous in E. granulata (fig. 294). Inner walls are also a little thickened. Lateral walls are thin and straight. Stomata are more numerous on the lower surface and are accompanied by ordinary epidermal cells. Guard-cells are in the plane of surrounding cells and the front cavity is placed in a depression formed by papillae.

The mesophyll is bifacial. Internal secretory organs are repre- sented by numerous large polygonal cells with tanniniferous contents in the spongy tissue in the leaf of P. Niruri. In the axis of E. gran- ulata there are numerous thick-walled elliptical cells with tanninifer- ous contents, interposed between the groups of bast fibres. Internal secretory cells are absent in the leaf and axis of E. granulata and P. Niruri respectively. Oxlate of lime is found in the form of numerous solitary crystals in the palisade tissues of the leaf in P. Niruri.

Veins are embedded and are enclosed in distinct green bundle- sheaths in E. granulata. Bundle-sheaths are not found in P. Niruri.

Structure of the axis — The epidermis in P. Niruri is two- layered ; cells of the outer layer have outer walls greatly thickened and granulated. Epidermis in E. granulata is single layered ; epidermal cells have outer walls thickened, granulated and convexely arch- ed outwards. Lateral walls are thin and straight. Primary cortex is composed of chlorenchyma. Collenchyma is developed in the ribs of P. Niruri.

Pericycle forms a loo?e ring of groups of bast fibres in P. Niruri, while E. granulata it is represented by isolated bast fibres. Wood forms a composite hollow cylinder with vessels distributed uniformly in incomplete rows in interfascicular wood prosenchyma. Vessels are more numerous in E. granulata. Medullery rays are uniseriate and numerous.

Pith consists of very thin-walled cells.

LILIACEAE.

Asparagus racemosus Wilkl Var. javanica Bah. — Epider- mal cells with dark-brown granules. Cork subepidermal. Pericycle forming a composite ring of stone-cells. Vascular bundles scattered in a concentric fashion in the ground tissue. Ground tissue formed of cells with walls thin aud lignified.

Structure of the Axis. — The epidermis consists of tabular cells. Epidermal cells have outer walls a little thickened and are filled with dark-brown granules. Lateral walls are thin and straight. Cork is subepidermal and is formed of thin-walled cork cells. The pericycle forms a composite ring of stone-cells outermost layer of which con- sists of a little larger stone-cells with larger lumina. Vascular system consists of numerous bundles which are scattered in the ground tissue and are roughly arranged in rings. Bundles get smaller towards the periphery. The ground tissue is formed of cells with walls thin and lignified. The central portion of the ground tissue enclosed by the innermost ring of bundles consists of very thin-walled cells.

CQMMELINACEAE.

Commelina albescens Eassk. — Pigs. 296, 297. Epidermal cells of the leaf tabular, thin-walled and with outer walls flat. Stomata on both the surfaces and accompanied by subsidiary cells. Mesophyll of palisade tissue on the upper side and of arm-palisade tissue on the lower. Internal glands in the form of cells with tanniniferous contents. Bundles of acicular raphides in lower epidermal cells. Clothing hairs on the leaf in the form of uniseriate bracket-shaped trichomes. Pericycle forming a composite ring of stone-cells. Collenchyma subepidermal. Assimilatory tissue lacunar Vascular bundles apposed to the stone-tissue of pericycle. Numerous isolated secretory receptacles surrounded by parenchyma in the ground tissue. Structure of the Leaf. — The epidermis consists of thin-walled tabular cells which are larger on the upper surface. Outer walls are flat and lateral walls are thin and straight.

Stomata are more numerous on the lower surface and are accom- panied by subsidiary cells. Guard-cells are in the plane of subsidiary cells which are elevated. The front cavity is on a level with the surface. Stomata on the axis have the same characters as of those on the leaf.

The mesophyll is composed of palisade tissue on the upper side and of loose arm-palisade tissue on the lower with an extensive system of intercellular spaces. Internal glands occur in the form of a few cells with tanniniferous contents in the mesophyll. Oxalate of lime is found in the form of bundles of acicular raphides in lower epidermal cells of the leaf ; it does not occur in the axis.

Leaves are many -ribbed. Veins of the ribs are vertically trans- current below by sclerenchyma. Smaller veins are embedded. Veins are enclosed in green bundle-sheaths.

Hairy covering consists of a few clothing hairs. They are unise- riate and bracket-shaped and are composed of a unicellular dome- shaped pedestal seated on epidermal cells, a long neck-cell and of a terminal cell bent like a hook, the tip being sharp and solid. Hairs are absent on the axis. External glands do not occur on the leaf and axis.

Structure of the Axis. — The epidermis consists of tabular cells with outer walls thickened and convexly-arched outwards. Lateral walls are thin and straight. The cortex is composed on its outer side of subepidermal collenchyma and on its inner side of assimil- atory tissue of arm-palisade cells arranged in a lacunar manner. The pericycle forms a composite ring of stone-cells. The vascular system is composed of scattered vascular bundles usually apposed to the pericyclic stone-cell ring and protected on their inner side by thin arcs of stone-cells.

The ground tissue is formed of large thin-walled parenchymatous cells filled with starch grains. It is characterised by the occurrence of numerous isolated secretory receptacles surrounded by small-celled parenchyma.

CYPERACEAE.

Cypeurs niveus Retz.— Figs.'298, 299. Margins bluntly point- ed and supported by stereome bundles. Extensive articulation tissue on the upper side of the leaf. Stomata on the lower side only. Front cavity on a level with the surface. Veins embedded and more or less in a single layer, large ones alternating with the smaller. All veins apposed to the stereome girders except a few very small ones. A few larger veins vertically transcurrent above and below by stereome. Bundle-sheaths, when present, internal. Mechanical tissue in the leaf in the form of isolated subepidermal girders below the veins, and of a few isolated girders on the upper side placed at regular intervals. T. S. of the axis triangular. Assimilatory tissue in the axis forming arcs or girders of palisade cells round the peripheral bundles. Mechanical tissue in the axis in the form of isolated sub-epidermal girders, larger ones alternating with the smaller. Ground tissue not differentiated in the centre into pith.

Cypems arenarius Retz. — Margins bluntly pointed without any supporting stereome bundles. Stomata only on the lower surface and with the front cavity depressed. Obconical groups of elongated cells occurring below the epidermis even in the absence of stomata. Veins embedded. Smaller veins near the lower epidermis. Bundle- sheaths, when present in leaf or axis, internal. Mechanical tissue in the form of isolated sub-epidermal girders below smaller veins. T. S. of the axis circular. Assimilatory tissue in the axis forming arcs or girders of palisade cells round peripheral bundles. Mechanical tissue in the axis forming numerous isolated girders, larger ones alterna- ting with the smaller. Ground tissue not differentiated in the centre into pith.

Cyperus conglomeratus Rottb.— Figs. 300, 301, 302. Mar- gins bluntly pointed and supported by stereome bundles. Extensive articulation tissue on the upper side. Stomata only on the lower surface. Front cavity depressed. Obconical groups of elongated cells occurring below the epidermis even in the absence of stomata. Bundle-sheaths, when present, internal. Veins embedded and ar- ranged in an alternating fashion in two rows. Smaller veins nearer the lower epidermis. Mechanical tissue in the leaf in the form of isolated sub-epidermal girders below all smaller veins and of a single long sub-epidermal girder on the upper surface near the margin. T. S. of the axis circular. Assimilatory tissue, in the axis forming arcs or girders of palisade cells round the peripheral vascular bundles. Mechanical tissue of sub-epidermal girders, alternating with the peri- pheral bandies and apposed to the girders. A few vessels enclosed in a thick ring of stereome in the ground tissue. Ground tissue differ- entiated in the centre into pith.

Cyperus rotundus L — Figs. 303, 304, 305, 306, 307. Margins rounded and without supporting stereome bundles. Upper epidermis modified into articulation tissue. All veins embedded. Larger veins nearer the lower epidermis and the smaller ones in the middle of the mesophyll. Bundle-sheaths, when present, internal. Isolated sub- epidermal girders below all larger veins and those on the upper side developed alternately above the larger veins. T. S. of the axis trian- gular. Of sub-epidermal girders in the axis, larger ones alternating with smaller ones. Assimilatory tissue forming arcs or girders of palisade cells round the peripheral bundles. Ground tissue differ- entiated in the centre into pith.

Fimbristylis tenera Boeck.— Fig. 308. Margins angular, the two angles supported by stereome bundles. Upper epidermal cells forming articulation tissue. Stomata only on the lower surface. Front cavity elevated above the surface. Veins embedded and arranged in a single row in the middle. Bundle-sheaths when present internal. Mechanical tissue in the leaf in the form of isolated sub-epidermal girders on the upper surface, at the angles of the margin and on the lower side of the mid-rib. T. S. of the axis circular and grooved. Assimilatory tissue in form of arcs or girders of palisade cells round the peripheral bundles. Vascular bundles below the furrows larger and longer and without protecting stereome girders. Mechanical tissue in the axis in the form of isolated sub-epidermal girders in the ribs. Ground tissue not differentiated in the centre into pith.

Scirpus quinquefarius Ham. L— Figs. 309, 310. Leafless. T. S. of the axis circular. Front cavity on a level with the surface. Assimi- latory tissue of palisade cells below and between stereome bundles. Smaller vascular bundles peripheral and placed in the assimilatory tissue ; larger ones placed in the ground tissue. Bundles enclosed in an outer ring of polygonal colourless cells and an inner ring of stone- colls. Mechanical tissue in the form of isolated sub-epidermal stereome girders. Ground tissue characterised by a system of very large air spaces.

(Tu be Continued).

Plate XXIX

289-290. Salsola foctida.

289. T. S. of the leaf.

Oc. 2 Com. ; Ob. 3 mm. Ap.

290. T. S. of the axis.

Oc. 2 Com. ; Ob. 3 mm. Ap. 291-292. Oalligonum polygonoides.

291. T. S. of the leaf showing a

stoma and a glandular hair. Oc. 6 Com. ; Ob. 3 mm. Ap.

292. T. S. of the axis.

Oc. 4 Com. ; Ob. 8 mm. Ap.

293. Polygonum plebejum.

Oc. 4 Com. ; Ob. 8 mm. Ap.

294. Euphorbia granulata. T. S. of the leaf.

Oc. 4 Com. ; Ob. 3 mm. Ap.

295. Phyllanthus Niruri.

T. S. of the axis as far as the

pericycle. Oc. 6 Com. ; Ob. 8 mm. Ay.

N.B.— To get the original dimensions multiply by 1-7.

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Plate XXX

296-297. Commelhia albescens.

296. T. S. of the axis.

Oc. 4 Com. ; Ob. 8 mm. Ap.

297. Internal gland in the axis. Oc. 4 Com. ; Ob. 3 mm. Ap.

298-299. Cyperus niveas.

298. T. S. of the leaf.

Oc. 6 Com. ; Ob. 8 mm. Ap.

299. Stoma on the leaf.

Oc. 6 Com.; Ob. 3 mm. Ap.

300-302. Cyperus conglomcratus

300. T. S. of the leaf.

Oc. 4 Com.; Ob. 3 mm. Ap.

301. Stoma on the leaf.

Oc. 4 Com. ; Ob. 3 mm. Ap.

302. T. S. of the axis.

Oc. 6 Com. ; Ob. 8 mm. Ap. 305. Cyperus rotundus. Stoma on the leaf. Oc. 8 Com. ; Ob. 3 mm. Ap.

iV.fi.— To get the original dimensions multiply by 17.

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Plate XXXI

303-307. Gyperus rotundus.

303. T. S. of the leaf at the mid-rib.

Oc. 6 Com. ; Ob. 8 mm. Ap.

304. T. S. of the leaf near the

margin. Oc. 2 Com. ; Ob. 3 mm. Ap.

306. T. S. of the axis at the

angle. Oc. 2 Com. ; Ob. 8 mm. Ap.

307. T. S. of the axis between the angles.

Oc. 2 Com.; Ob. 8 mm. Ap.

308. Fimbristylis tcnera.

T. S. of the leaf near the margin.

Oc. 2 Com.; Ob. 3 mm. Ap. 309-310. Scir2)its quinqucfarius,

309. T. S. of the axis.

Oc. 4 Com. ; Ob. 8 mm. Ap.

310. T. S. of the axis.

Oc. 6 Com. ; Ob. 8 mm. Ap.

N.B.— To get the original dimensions multiply by 1*7

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