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

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​THE
Journal of Indian Botany.
Vol. II. SEPTEMBER, 1921. Nos. 3 & 9.
THE PHYSIOLOGICAL ANATOMY OF THE PLANTS OF THE INDIAN DESERT
BY
T. S. Sabnis, B.A., M.SC,
St. Xavier's College, Bombay. (Continued from p. 167). CYPERAC EAE— (Contd.) Scirpus maritimus L— Figs. 311, 312, 313, 314, 315, 316, 317. Margins pointed and protected by stereome bundles. Stomata on both the surfaces of the leaf-blade with the front cavity depressed. Stomata on the leaf-sheaths on the outer side only. Mesophyll in the leaf-blade wholly of palisade cells on either side of stereome gir- ders. Lysigenous cavities alternating with the veins in the leaf-blade and leaf-sheath. Veins in the leaf-blade vertically transcurrent above and below by aqueous cells. Articulation tissue not developed except for aqueous cells on either side of the veins. Mechanical tissue in the leaf-blade forming I-girders, webs being formed by unmixed vascular bundles ; and that in the leaf-sheath in the form of isolated sub-epidermal girders on the outer side above the veins. Veins enclosed in an outer ring of large polygonal colourless cells and of an inner ring of stone-cells. T. S. of the axis triangular. Assimilatory tissue in the axis of palisade cells between stereome girders. Vascular bundles enclosed in rings of stereome. Peripheral bundles apposed to the stereome girders. Mechanical tissue in the form of isolated sub- epidermal girders, those at the angles forming composite large strands. Ground tissue not differentiated in the centre into pith and of cells with granular contents. Structure of the leaf. — The epidermis consists of cells with outer walls flat, greatly thickened and silicified. Inner walls are angular and fit into the sub-epidermal tissue so as to form a com​pact structure. Lateral walls are thin and straight. The upper epidermis forms the aqueous articulation tissue and is many-layered in species of Cyperus. The articulation tissue in the mid-rib of G. rotundas (fig. 303) and S. mar Minus consists of elongated cells narrowed above so as to form a specialised articulation tissue to regulate the upward curving movements of the leaf-halves by the difference in the turgidity of these cells. As these cells are greatly narrowed in their upper portion, the leaf-halves can come quite close together and thus protect the articulation tissue from suffering much loss of water in times of very dry weather. Such a tissue in the mid-rib is not necessary in other species of Cyperus, as there is abundant aqueous tissue and as the leaf-halves are very short. In F. tenera the articulation is 2-3-layered in the mid-rib.
Margins are rounded in C. rotundas or are bluntly pointed as in other species of Cyperus and in S. maritimus or peculiarly angular in F. tenera (fig. 308).
Stomata in species of Cyperus and in F. tenera occur only on the lower surface of the leaf ; in S. maritimus they are more numerous on the lower surface. The occurrence of stomata only on the lower surface is due to the presence of the assimilatory tissue below the lower epidermis ; their presence on the upper surface, where the articulation tissue is developed, will accelarate transpiration and will thus perform a function opposite to that of the articulation tissue. The occurrence of stomata on both the surfaces in S. mariti- mus is partly due to the absence of aqueous tissue near the surface and partly to the presence of photosynthetic tissue along both the surfaces. The guard-cells are elevated and are accompanied by subsidiary cells in all the members. The front cavity is placed on a level with the surface in C. rotundas, while in other species of Cyperus and in S. maritimus it is placed in a depression formed by outer thickened epidermal walls ; in F. tenera it is elevated above the surface.
The stomata on the leaf as well as those on the axis of all members have on obconical sub-stomatal cavity which is lined by elongated cells forming an obconical tissue. The obconical cavities are quite conspicuous in C. conglomerates (figs. 299, 303, 302) and also occur below the epidermis even where stomate do not occur. The obconical shape of sub-stomatal cavities and also that of the sub-stomatal tissue forms a characteristic feature of members of Cyperaceae. Stomata occur on the outer surface of the leaf-sheath of S. maritimus. Stomata on the leaf-sheath as well as those on the axis like those on the leaf.
The photosynthetic tissue in species of Cyperus and in F. tenera is composed of complete girders of tubular palisade cells round all the ​veins except the vertically transcurrent ones in G. niveus, where it forms arcs of palisade cells on the sides of the veins (fig. 298). In the leaf-blade of S. maritimus tubular palisade cells form groups below the epidermis, the adjacent groups being separated by a tissue of loosely arranged arm-palisade cells which are afterwards destroyed to form cavities alternating with the veins. In C. rotundas there is a tissue of thin-walled parenchymatous cells occurring below and between the veins and similarly forming cavities below the stomata. Cells above the zone of the palisade tissue in species of Cyperus and those on either side of the veins in S. maritimus form the aqueous articulation tissue with a two-fold function, that of collecting water and that of regulating the upwards curving movements of the leaf-halves. The abundance of the aqueous articulation tissue in species of Cyperus can be accounted for by the abundance of veins. In F. tenera leaf-blades are thin and the veins together with their girders of palisade cells and a few secretory cells occupy the whole space between the epidermis on either side.
In the leaf- sheaths of S. maritimus palisade cells form small groups on the sides of the isolated sub-epidermal girders. The veins, except those at the angular portions, are separated by a tissue of stel- late cells which, later on, are destroyed and cavities are formed. The occurence of these lysigenous cavities in abundance is the result of the water-supply being insufficient to maintain all the tissues in a fully developed leaf-blade. The thin-walled parenchymatous cells do not form any important tissue ; they, therefore, lose their turgidity, shrivel up and are destroyed to form cavities.
Internal glands are represented by numerous secretory cells with tanniniferous contents near the veins in the leaf-blades and leaf- sheaths and in neighbourhood of vascular bundles in the axis. A few secretory cells occur in the ground tissue of the axis.
Veins are numerous and are confined to the lower half of the mesophyll except in F. tenera and S. maritimus,' in which they are placed in the middle of the mesophyll. Larger veins usually alternate with smaller ones and when veins occur in two planes those in one plane alternate with those in the other (fig. 300). This gives rigidity to the leaf-blade and accommodates a larger number of veins in a small space of the lower half of mesophyll. In species of Gyperus and in
F. tenera smaller veins are enclosed in two rings, the outer one of stereome and the inner one of green sheath-cells. Larger veins are enclosed in a single outer ring of stereome and the inner ring is represented by two arcs of sheath-cells. Some of the larger veins in
G. nivens are vertically transcurrent above and below by stereome bundles (fig. 298). In F. tenera a single large vein occurs in the ​angular margin and is supported by angular sfcereome bundles ; other veins are small and are placed in the middle of the mesophyll.
In the leaf-blade and leaf-sheath of S. maritimus veins are enclosed in an outer ring of stereome and in an inner ring of large colourless polygonal cells. All the veins are vertically transcurrent ; those in the leaf -blade are vertically transcurrent above and below by aqueous cells and those in the leaf-sheath are apposed to lower epidermis and are vertically transcurrent above by aqueous cells.
The mechanical tissue in G. rotundas (figs. 303, 304) and in C. nivens (fig. 298) is composed of isolated sub-epidermal girders, which are more numerous on the lower surface. On the lower surface the subepidermal girders are found above the veins and on the upper surface they occur at regular intervals, being developed more or less above every alternate vein in (J. rotundas. In G. niveus there are some I-girders in association with the larger veins, webs of which are formed by unmixed vascular bundles. In C. conglomcratus and in G. arenarius isolated sub-epidermal girders occur only on the lower surface above the lower veins; and there is a long sub epidermal girder on the upper surface near one margin (fig. 300). The mechanical tissue in F. tenera is represented by sub- epidermal girders in the angular margins and below the mid-rib which is greatly projected downwards. The mechanical tissue in leaf-blades of S. maritimus (fig. 312) consists of I-sub-epidermal girders webs of which are formed by mixed vascular bundles of the veins and of small sub- epidermal girders in the margin and on the lower surface of the mid-rib. The sub-epidermal girders in leaf-sheaths occur on the outer surface above the veins and at the angles.
The occurrence of extensive mechanical tissue on the lower surface protects the lower surface against tension produced in the upwards-curving movement of the leaf-halves which are brought about by diminution in turgidity of the cells in the articulation tissue in the upper half of the leaf-blade.
Hairs, either clothing or glandular, are absent in all the members.
Structure of the axis. — The epidermis consists of tabular cells with outer walls flat, greatly thickened and silicified. Inner walls are very thin and angular and lateral walls are thin and straight. Epidermal cells between the girders in species of Scirpus are uniformly sclerosed.
The assimilatory tissue in species of Cyperus and in F. tenera is composed of girders and arcs of tabular palisade cells round smaller veins and on sides of the upper portion of larger veins respectively. In S. quinquefarius (figs. 309, 310) palisade tissue occurs between and below the girders, while in 8. maritimus (fig. 315) it occurs between the girders. ​ The vascular system consists of numerous peripheral bundles seated on sub-epidermal stereome girders in all members except S. quinquefarius and of a few inner bundles embeded in the ground tissue. Peripheral bundles are of two sizes, larger ones alternating with the smaller. Smaller bundles in species of Cyperus in F. tenera and in S. maritimns are enclosed in an outer ring of stone-cells and in an inner ring of green sheath-cells ; larger bundles are enclosed in a single ring of stone-cells which is many layered on the inner side. In G. arenarius, besides the peripheral bundles seated on the girders there are other small bundles not protected by any sub-epidermal girders and alternating with the former. Smaller bundles in S. quinquefarius (fig. 310) occur in the assimilatory tissue and are not apposed to the sub-epidermal girders ; the larger ones are placed in ground tissue strands.
The ground tissue consists of thin- walled parenchymatous cells and is traversed in its outer portion by vascular bundles ; it is not differentiated in the centre into pith except in C. rotundus in which the central tissue is composed of a few larger thin-walled cells. The ground tissue in S. quinquefarius is represented by one-layered plates of parenchymatous cells enclosing large air-spaces. Vascular bundles occur in the traversing plates. The occurrence of sclerenchyma in the ground tissue of S. quinquefarius is the result of its being found on wet ground.
General Review. — Epidermal cells have outer walls greatly thick- ened and silicified. Inner walls are angular and lateral walls are straight. The upper epidermis is modified to form the aritculation tissue in species of Cyperus and in F. tenera. Stomata occur only on the lower surface in species of Cyperus and in F. tenera where the upper epidermis forms the articulation tissue ; they are found on both the surface in S. maritamus in which the epidermis on either side is not modified into the articulation tissue. The guard-cells are elevated and are accompanied by subsidiary cells. The front cavity is either placed in a depression formed by the outer thickened epidermal walls or it is elevated above the surface. Stomata on the leaf as well as those on the axis are characterised by obconical cavities around which are also developed obconical groups of elongated obli- quely placed cells. The photosynthetic tissue in the leaf and axis consists of tabular palisade cells. Veins are numerous and are arranged in a single row or in two rows larger veins alternating with the smaller. Smaller veins and vascular bundles in the axis in species of Cyperus and in F. tenera are enclosed in an outer ring of stereome and in an inner ring of sheath-cells ; larger veins are enclosed ​in a single ring of stone-cells. In S. maritimus veins as well as the vascular bundles in the axis are enclosed in an outer ring of large colourless polygonal cells and in an inner ring of stereome.
The mesophyll in 0. rotundus and in S. maritimus is character- ised by a system of lysigenously formed cavities resulting from a deficient supply of water. Internal secretory cells with tanniniferous contents are numerous near the veins in the leaf and in the neighbourhood of vascular bundles in the axis. The mechanical tissue in the leaf as well as in the axis is mostly composed of isolated sub-epidermal girders except in 'the leaves of S. maritimus in which I-girders are found. Vascular bundles in the axis are numerous and peripheral, larger bundles alternating with the smaller.
The ground tissue is composed of thin-walled parenchymatous cells with a differentiated central tissue of much larger cells in G. rotundus. The ground tissue in S. quinquefarius is characterised by large air spaces. S. quinquefarius occurs always on wet ground and well developed aerenchyma is consequently quite necessary.
The axes of S. maritamus are enclosed in close fitting leaf-sheaths which protect the axes against insolation and also give, to some extent, rigidity to the axes against the violence of the desert winds. Leaf-blades which are as long as the axis are held in position by means of leaf-sheaths and cannot therefore be easily separated from the axis by the strong desert winds. The long leaf-blades, but for the leaf-sheaths, would have been torn off from their bases by the desert winds.
Hairs either clothing or glandular are not found on the leaf and axis.
GRAMINEAE
Digitaria sanguinalis Scop. var. ciliaris Pram.— Grooved on the lower surface. Hairs spiny on the leaf and absent on the axis. Stomata more numerous on the lower surface. Articulation tissue not extensive and found on the upper side above the grooves. Palisade cells forming complet9 girders. Veins embedded and enclosed in complete sheaths. Mechanical tissue in the leaf in the form of I- girders. Webs formed by unmixed vascular bundles. Mechanical tissue in the axis forming isolated sub-epidermal girders and an internal stereome tube. Assimilatory tissue absent in the axis. Smaller bundles embedded in the stereome tube. Large bundles few in the medullary tissue. Medullary tissue of thin-walled cells.
Panicum turgidum Forsh, — Eigs..319, 320, 321. Equally deeply grooved on both sides. Margins blunt and with large stereome bundles. Hairs spiny and absent on the axis. Stomata more ​numerous on the upper surface. Articulation tissue extending be- tween two surfaces. Veins few, embedded and with complete sheaths. Palisade cells forming complete girders. Mechanical tissue forming I-girders in association with all the veins. Mechanical tissue in the axis forming stereome tube supplimented by I-girders. Webs formed by mixed vascular bundles. Assimilatory tissue in the axis formed of palisade cells and with a continuous layer of sheath cells on its inner side. Smaller vascular bundles forming webs of I-girders. Larger vascular bundles in the medullary tissue. Medullary tissue of thin- walled cells.
Panicum antidotale Betz.—Eig. 322. Leaf deeply but unequally grooved on two surfaces. Hairs spiny and absent on the axis. Stomata more numerous on the lower surface. Rows of articul- ation tissue cells not as conspicuous as in P. turcjiclum. Veins numerous. Palisade cells forming complete girders round the veins. Mechanical tissue in the form of I-girders in association with larger veins. Veins embedded and provided with complete sheaths. Assimilatory tissue in the axis formed of chlorenchyma. Mechanical tissue in the axis formed by stereome tube supplemented by sub- epidermal I-girders. Webs formed by unmixed vascular bundles. Some of the smaller vascular bundles embedded in the assimilatory tissue. Smaller vascular bundles provided with arcs or complete girders of sheath-cells. Some of the larger bundles embedded in the stereome tube. Larger bundles numerous in the medullary tissue Medullary tissue of thin-walled cells.
Cenchrus catharticus Del.— Figs. 323, 324. Leaves deeply grooved on the upper surface. Epidermal cells vertically elongated. Margins blunt and with large stereome bundles. Stomata more numerous on the lower surface. Hairs spiny and absent on the axis. Articulation tissue extending between two surfaces. Veins provided with complete sheaths. Larger veins vertically transcurrent above and below by aqueous cells and sub-epidermal stereome girders. Larger veins placed in a higher plane and situated below the ridges. Mechanical tissue in the leaf in the form of isolated sub-epidermal girders on the lower side of the veins in furrows and on both the sides of the veins in the ridges forming I-girders. Webs formed by mixed bundles. T. S. of the axis horn-shaped. Assimilatory tissue forming strands of chlorenchyma between smaller bundles. Mechani- cal tissue in the axis forming a stereome tube supplimented by I-girders. Webs formed by unmixed small bundles. Smaller bundles forming webs of I-girders. Of the larger bundles some embedded in the stereome tube and some in the medullary tissue. Medullary tissue of thin-walled cells. ​ Latipes senegalensis Euntli. — Uig. 325. Deeply grooved on the upper surface. Margins pointed and with small stereome bundles. Hairs spiDy and absent on the axes. Stomata more numerous on the upper surface. Articulation tissue in the upper portion of the meso- phyll. Veins provided with horse-shoe shaped sheaths incomplete below. Veins vertically transcurrent. Mechanical tissue in the leaf in the form of I-girders. Assimilatory tissue absent in the axis. Mechanical tissue in the form of subepidermal stereome tube. Small bundles embedded in stereome tube. Large bundles few in the medullary tissue. Medullary tissue of very thick-walled cells filled with granular contents.
Elionurus Royleanus Nees.— Figs. 326, 327. Epidermal cells on the upper surface vertically elongated and papillose. Surface not grooved. Hairs unicellular, long and only on the upper surface. Margins blunt and with small stereome bundles. Epidermal cells forming articulation cells. Epidermal cells on the lower surface tabular and with angular thickenings on outer walls. Stomata only on the upper surface. Palisade cells forming complete girders round smaller veins. 'Veins provided with sheaths. Upper cells of sheaths of vertically transcurrent veins forming aqueous cells. Larger veins apposed to epidermis above and vertically transcurrent below by stereome. Mechanical tissue in the leaf in the form of isolated sub- epidermal girders on the lower side of some of the larger veins. Assimilatory tissue absent in the axis. Mechanical tissue in the axis forming a sub-epidermal stereome tube. Smaller bundles embedded in stereome tube. Larger bundles few in medullary tissue. Medullary tissue of thin-walled cells.
Elionurus hirsutUS Man.— Figs. 328, 329, 330. Deeply groov- ed on the upper surface. Lower surface furrowed below the larger veins. Margins pointed and with large stereome bundles. Hairs spiny, long and unicellular. Stomata more numerous on the lower surface. Articulation tissue extending between two surfaces near the margin and forming extensive tissue between the upper epidermis and veins towards the margin. Palisade cells forming complete girders round non-transcurrent smaller veins. Larger veins alternating with smaller ones and situated in a higher plane. Larger veins near the margin vertically transcurrent. Mechanical tissue in the leaf in the form of I-girders towards the margin, of isolated sub-epidermal girders on the lower surface and of stereome-ring iDside the sheath round non-transcurrant smaller veins. Assimilatory tissue in the axis forming a continuous ring of chlorenchyma. Smaller bundles with complete sheaths and embedded in assimilatory tissue. Of the larger bundles the peripheral ones embedded in stereome tube and inner ​ones found in the medullary tissue and enclosed in stereome rings. Mechanical tissue in the axis in the form of stereome tube. Medull- ary tissue of thick- walled cells.
Andropogon foveolatus Del— Figs. 331, 332, 333. Not much grooved on either surface. Margin blunt and with large stereome bundles. Hairs unicellular, long and bluntly pointed. Articulation tissue one-layered groups. Palisade tissue and bundle-sheaths in the form of rings round smaller veins and of arcs on sides of vertically transcurrent veins. Mechanical tissue in the leaf sin the form of I-girders in association with vertically transcurrent veins and of isolated sub-epidermal girders on the lower side of other veins. T. S. of the axis horseshoe shaped. Mechanical tissue in the axis forming a sub-epidermal stereome tube. Assimilatory tissue absent in the axis. Smaller bundles embedded in stereome tube. Larger bundles few in the medullary tissue. Medullary tissue of thin-walled cells.
Andropogon annulatUS Forsk — Fig. 334. Not much grooved on either side. Margin pointed and with large stereome bundles. Hairs unicellular, long and bluntly pointed. Articulation tissue in the form of one layered groups. Palisade cells and sheath-cells forming complete rings round smaller veins and arcs on sides of vertically transcurrent veins. Mechanical tissue in the leaf in the form of I-girders in association with vertically transcurrent veins and of isolated sub-epidermal girders on the lower side of other veins. T. S. of the axis horse-shoe shaped. Mechanical tissue in the axis forming a sub- epidermal stereome tube. Assimilatory tissue absent in the axis. Smaller bundles embedded in the stereome tube. Larger bundles few in the medullary tissue. Medullary tissue of thin-walled cells.
Aristida funiculata Rupr — Figs. 335, 336, 337, 338. Upper surface deeply grooved. Margins bluntly pointed and with large stereome bundles. Hairs spiny. Palisade tissue and sheath-cells forming complete girders round smaller veins and arcs on sides of vertically transcurrent veins. Mechanical tissue in the leaf in the form of I-girders in association with vertically transcurrent veins and of isolated sub-epidermal girders on the lower side. Mechanical tissue in the axis forming a stereome tube supplimented by sub-epidermal I-girders. Webs formed by unmixed vascular bundles or by strips of stereome. Assimilatory tissue in the axis chlorenchymatous. Larger bundles in the medullary tissue and few. Medullary tissue of thin- walled cells.
Aristida hirtigluma Steud.— Figs. 339, 340. Grooves on the upper surface not deep. Margin pointed and with small stereome bundles. Hairs spiny. Articulation tissue only in the upper half of mesophyll. Palisade tissue and sheath cells forming complete rings ​round smaller veins and arcs on sides of vertically transcurrent veins. Mechanical tissue in the leaf forming sub-epidermal I-girders in association with vertically transcurrent veins and isolated sub-epidermal girders on the lower side. Assimilatory tissue in the axis of palisade cells with a layer of cells resembling sheath-celis on the inner side. Mechanical tissue in the axis in the form of a stereome tube suppli- mented by isolated sub-epidermal I-girders. Webs formed by mixed vascular bundles or by strips of stereome. Larger vascular bundles in the medullary tissue and numerous. Medullary tissue of thin- walled cells.
Gracilea Royleana H. /. Figs. 341, 342, 343, 344. Deeply grooved on both surfaces. Margins blunt with large stereome bundles. Stomata more numerous on the lower surface. Hairs spiny and situated at the angles on the axis. Articulation tissue in the upper half of the mesophyll. All veins vertically transcurrent. Smaller veins with complete sheaths. Mechanical tissue in the leaf forming I-girders. Assimilatory tissue forming arcs above the smaller vascular bundles. T. S. of the axis flattened on the inner side and- semicircular and angled on the outer. Mechanical tissue in the axis in the form a stereome tube supplemented by sub-epidermal I-girders at the angles. Webs formed by mixed small vascular bundles. Larger vascular bundles all embedded in the stereome tube. Medullary tissue of thin- walled cells filled with starch grains.
Chloris villosa Pers. — Fig. 345. Grooves on the surfaces not deep. Epidermal cells toothed. Margins pointed and with small stereome bundles. Hairs spiny. Stomata more numerous on the lower surface. Articulation tissue extending between two surfaces. Palisade tissue forming arcs on sides of the veins. Veins vertically transcurrent. Bundle-sheaths complete round smaller veins. T. S. of the axis elliptical. Assimilatory tissue chlorenchymatous and placed in the plane of longer diameter. Mechanical tissue in the leaf in the form of I-girders and that in the axis in the form of a stereome tube and of a thin sub-epidermal layer of stereome. Smaller vascular bundles embedded in the stereome tube. Larger vascular bundles enclosed in stereome rings and numerous in the medullary tissue ; medullary tissue of thick- walled cells towards the pariphery and of thin-walled cells in the centre.
Eleusine flagellifera Nees.— Figs. 346, 347, 348. Deeply grooved on the upper surface. Margins blunt and with large stereome bundles. Hairs spiny, longer and arising from articulation cells on both sides. Hairs spiny on the axis. Stomata more numerous on the lower surface. Articulation tissue extending between two sur- faces. Palisade cells forming complete girders round smaller veins. ​Larger veins vertically transcurrenfc. Upper and lower cells of sheaths of vertically transcurrent veins aqueous. Sheaths complete round the veins. Mechanical tissue in the leaf in the form of I-girders and of isolated sub-epidermal girders on the lower side above smaller veins. T. S. of the axis elliptical. Assimilatory tissue in the axis chlorenchymatous. Mechanical tissue in the axis forming a stereome tube supplemented by I-girders. Webs formed by unmixed small vascular bundles. Smaller vascular bundles forming webs. Larger vascular bundles in the medullary tissue, few and with arcs of stereome on the outer side. Medullary tissue of thin-walled cells.
Eleusine aristata Ehrenb.— Figs. 349, 350. Not grooved. Epidermal cells on the lower surface vertically elongated and papillose. Hairs short, unicelluler and bluntly pointed. Stomata more nume- rous on the lower surface. Articulation tissue extending between the surfaces. Palisade cells forming complete girders round smaller veins ; veins provided with complete sheaths. Larger veins vertically trans- current. Mechanical tissue forming I-girders supplemented by isolated sub-epidermal girders on the lower side below smaller veins. Assimi- latory tissue in the axis forming groups of palisade cells. Mechanical tissue in the axis in the form of a stereome tubo supplemented by iso- lated subepidermal girders alternating with I-girders. Webs formed by unmixed vascular bundles. Larger vascular bundles in the medullary tissue, few and with arcs of stereome on the outer side. Medullary tissue of thin-walled cells.
(To be continued.) ​
Plate XXXII.
311-317. Scirpus maritimtts.
311. T. S. of the leaf-blade at the margin.
Oc. 4 Com. ; Ob. 8 mm. Ap.
312. T. S. of the leaf-blade be- tween the mid-rib and the margin.
Oc. 6 Com. ; Ob. 8 mm. Ap.
313. Stoma on the leaf.
Oc. 8 Com. ; Ob. 3 mm. Ap.
314. T. S. of the axis at the angle. Oc. 4 Com. ; Ob. 8 mm. Ap.
315. T. S. of the axis between the angles.
Oc. 6 Com. ; Ob. 8 mm. Ap.
316. T. S. of the leaf-sheath enclosing the axis.
Oc. 4 Com. ; Ob. 8 mm. Ap.
317. Internal gland in the axis. Oc. 6 Com. ; Ob. 3 mm. Ap.
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Plate XXXIII.
319-321. Panicum turgidum.
319. T. S. of the leaf.
Oc. 4 Com. ; Ob. 8 mm. Ap.
320. T. S. of the axis.
Oc. 4 Com. ; Ob. 8 mm. Ap.
321. Stoma on the axis.
Oc. 6 Com. ; Ob. 3 mm. Ap. 322. Panicum antidotale.
T. S. of the axis.
Oc. 4 Com. ; Ob. 8. mm. Ap. 323-324. Cenchrus catharticus. 323. T. S. of the leaf.
Oc. 6 Com. ; Ob. 8.'mm. Ap.
324. T. S. of the axis.
Oc. 6 Com. ; Ob 8 mm. Ap. 325. Latipes senegalensis.
T. S. of the leaf.
Ou. 4 Com. ; Ob. 3 mm. Ap. 326-327. Elionurus Royleanus.
326. T. S. of the leaf.
Oc. 6 Com. ; Oc. 8 mm. Ap.
327. Stoma on the leaf. Oc. 8 Com. ; Ob. 3 mm.
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Plate XXXIV.
328-330. EUonuriis hirsutus.
328. T. S. of the leaf at the mid-rib including the vas- cular bundle of the mid-rib.
Oc. 4 Com. ; Ob. mm. Ap.
329. T. S. of the leaf between the mid-rib and the mar- gin.
Oc. 4 Com. ; Ob. 8 mm. Ap.
330. T. S. of the axis.
Oc. 4 Com.; Ob. 8 mm. Ap. 331-333. Andropogon foveolatus.
331. T. S. of the leaf.
Oc. 6. Com. ; Ob. 8 mm. Ap.
332. T. S. of the leaf showing the margin.
Oc. 6 Com. ; Ob. 8 mm. Ap.
333. Stoma on the leaf.
Oc. 6 Com. ; Ob. 3 mm. Ap.
334. Andropogon annulatus T. S. of the leaf.
Oc. 6. Com. ; Ob. 8 mm. Ap. 335-338. Aristida funiculata.
335. T. S. of the leaf.
Oc. 6 Com. ; Ob. mm. Ap.
336. T. S. of the leaf showing the articulation tissue.
Oc. 6 Com. ; Ob. 8 mm. Ap.
337. T. S. of the axis.
Oc. 6 Com. ; Ob. 3 mm. Ap.
338. Stoma on the axis.
Oc. 6 Com. ; Ob. 3 mm. Ap. 339-340. Aristida hirtigluma.
339. T. S. of the leaf.
Oc. 4 Com.; Ob. 8 mm. Ap.
340. T. S. of the axis. Oc. 4 Com, ; 8 mm. Ob. Ap.
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Plate XXXV.
341-344. Gracilea Boyleana.
341. T. S. of the leaf.
Oc. 4 Com. ; Ob. 3 mm. Ap.
342. Glandular hair on the axis. Oc. 4 Com. ; Ob. 3 mm. Ap.
343. T. S. of the axis.
Oc. 4 Com. ; Ob. 8 mm. Ap.
344. T. S. of the axis at the angle.
Oc. 6 Com. ; Ob. 3 mm. Ap. 345. Chloris villosa. T. S. of the leaf. Oc. 4 Com. ; Ob. 3 mm. Ap.
346-348. Eleusine flagellifera. 246. T. S. of the leaf.
Oc. 4 Com. ; Ob. 8 mm. Ap. 347- Stoma on the leaf.
Oc. 6 Com. ; Ob. 3 mm. Ap.
348. T. S. of the axis.
Oc. 4 Com. ; Ob. 8 mm. Ap. 349-350. Eleusine aristata.
349. T. S. of the leaf.
Oc. 6 Com. ; Ob. 8 mm. Ap.
350. T. S. of the axis.
Oc. 6 Com. ; Ob. 8 mm. Ap.
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