Epidermal tissue system consists of the epidermal layers occurring on the adaxial (upper) and abaxial (lower) sides. Phloem carries prepared food to other parts of a plant. A section through the leaf of bamboo (Bambusa spp. Thus these cavities, unlike the usual intercellular spaces, are formed lysigenously. The Internal Structure of a Leaf Diagram below is a cross section of a dicotyledonous leaf that shows all the different tissues that make up the leaf. A good number of trichomes develop from the cells bordering the depression. The rest of the ground tissue is composed of thin-walled parenchyma with distinct intercellular spaces. The gaseous exchange occurs through this stomata. The bundles are collateral and closed ones. The lenticels allow air to pass through them. These cells consti­tute what is known as bundle sheath extension. spongy mesophyll. Chloroplasts are abundantly present, which particularly occur along the radial walls of the cells. Within each leaf, the vascular tissue forms veins. Difficulty. The differentiation of tissues into epider­mal, ground and vascular is clear. Often these ends bend into minute specialised photosynthetic areas known as vein islets or they may just extend into the mesophyll. These are long columnar cells rather tightly arranged with scanty intercellular spaces. Give "one word names" for the processes by which these raw materials move across the leaf, as seen in the diagram. Mesophyll hardly shows differentiation between palisade and spongy cells. Slightly sunken stomata are present on the lower side. Explain The Internal Structure Of Dicot Leaf Brainly In Describe The Anatomical Structure Of A Dicot Leaf Qs Study ... Ts Of Leaf Diagram Class 10 Nymphaea Sclerenchyma cells occur in patches on both edges of the bundles, obviously for giving mechanical strength. Thus the bundle is not in direct contact with the meso­phyll cells. The section (Fig. A number of vascular bundles occur in the form of a band; some bundles are small and some of them are quite large. Our mission is to provide an online platform to help students to share notes in Biology. Upper Epidermis: this is the tissue on the upper surface of the leaf. Leaves are very important vegetative organs, as they are chiefly concerned with the physiological process, photosynthesis and transpiration. The spongy cells are compara­tively much smaller and more or less isodiametric in shape. Whether they belong to epidermis or to the ground tissues from ontogenetic point of view can be determined by developmental studies. Collenchyma cells occur next forming hypodermis. Bundles are collateral and closed. The stomata are present on the lower epidermis, but they are sunken stomata located in a depression known as stomatal pit. While a compound … It exhibits the following internal structure (Fig. Leaf cells face two situations. The bundles are collateral and closed ones with xylem on the upper and phloem on the lower sides. 12 Questions | By Cancerred | Last updated: Dec 14, 2012 | Total Attempts: 5918 . The mesophyll does not show differentiation into palisade and spongy cells, but is made of rather compactly-arranged isodiametric cells. 622). An organ is a group of tissues that performs a specialized task. Settings. One or more layers of much larger thin-walled parenchyma cells occur next to epi­dermal layers—both adaxial and abaxial. Leaf Internal Structure - Diagram DIRECTIONS: Use your textbook, or internet sources to find pictures of the internals structure of a leaf. The petiole or the leaf stalk connects the lamina to the base, and thus supports it on the axis and exposes it to proper amount of light and air. Each is uniseriate, composed of a row of compactly-set tabular cells. The Epidermis An upper and … The exchange of oxygen, carbon dioxide and water vapors between the leaf cells and the air take place through stomata. Trichosclereids of peculiar shapes, often with deposition of calcium oxalate crystals are abundantly present. Describes how leaves are made of several different kinds of specialized tissues. The upper layer of a leaf is called the upper epidermis. They are located in the mesophyll. Here you can see many different types of leaf margins of the leaf. Disclaimer Copyright, Share Your Knowledge A transverse section would show the same plan of arrangement of tissues: It is uniseriate with tabular cells and a large number of epidermal outgrowths. > water - osmosis > CO 2 - diffusion. But the bundles entering the leaf occupy such a position that xylem occurs on the upper side and phloem on the lower. Often parenchyma cells of the sheath contain starch, then it may be called a ‘starch sheath’. The upper layer of a leaf is called the upper epidermis. 621): The two epidermal layers are composed of compactly-arranged tabular cells with cuticularised outer walls. A transverse section would show the following structure (Fig. The size of the bundle depends on the position one chooses to take in making a section. Internal Parts of a Leaf. Before sharing your knowledge on this site, please read the following pages: 1. The apical growth takes place at the early stage. It contains a prominent midrib at the center of the leaf blade which is the main vein. The xylem vessels usually break down and form lacunae which resemble the air chambers. Large air chambers are present in the mesophyll. The morphology of bundle sheath was considered to be uncertain, but it is now regarded as an endodermis (Fann), where Casparian strips in -some cases have been observed. A number of large air chambers occur at regular intervals towards abaxial side. Leaves take energy from the sun and use it to make food-the process of photosynthesis. A section through the leaf of waterlily (Nymphaea stellata of family Nyphaeaceae) would reveal the following anatomical structure (Fig. During the daytime when the mesophyll cells of leaves are carrying out photosynthesis and respiration side by side, the oxygen produced in photosynthesis is utilized in cellular respiration. The bundles remain surrounded by a row of parenchyma cells devoid of chloroplasts, which forms the bundle sheath. This is a question and answer forum for students, teachers and general visitors for exchanging articles, answers and notes. They are often differentiated into three layers—adaxial, abaxial and middle layers. 626) of the petiole of Piper betle of family Piperaceae is more or less heart-shaped with a distinct groove at one side and rounded at the other. A transverse section through the leaf of Banyan (Ficus benghalensis of family Moraceae) would reveal the anatomical characters (Fig. Just internal to epider­mis there are usually two layers of columnar cells with abundant chloroplasts. They are collateral ones with xylem on the inner and phloem on the outer side. These are present at regular intervals. The subepidermal cells have been desig­nated as hypodermis by older anatomists. Internal structure of dicot leaf anatomical structure of a dicot leaf dicot or dorsiventral leaf internal leaf structure. 624). lies between upper and lower epidermis and is the main site of…. The cells occurring beneath the marginal initials, known as submarginal initials, divide in all planes and produce the internal tissues of the leaf. MEMORY METER. Share Your PPT File. A good number of bundles of different sizes occur in the form of an arc. Leaf Structure And Its Functions/ Photosynthesis . A few common isobilateral leaves have been selected for the study of internal structures. Leaves are the main photosynthetic organs of the plant. (ii) Leaf-blade is enriched with reticulate venation. In this article, we propose to discuss about the internal structure of leaf. They are columnar cells with scanty intercellular spaces and remain arranged more or less at right angles to the upper epidermis. 619): Both upper and lower epidermal layers are uniseriate and com­posed of more or less oval cells with cuticularised outer walls. The rest of the ground tissue is made of thin-walled parenchyma with pretty large number of air chambers. During the development of the blade the basal part of the protrusion remains unexpanded which ultimately forms a meristem that gives rise to the petiole. Epidermis. internal structure of leaf. upper and lower epidermis. | Structure, Formation, and Examples, Five Kingdom Classification System Characteristics, 20 Types of Amino Acids with Definition and Classification, Economic Importance of Bacteria in different Field, Mimosaceae Family Plants, Characteristics & Economic Importance, Importance of Fungi with Ecological & Commercial Factors in Daily Life, Difference between Land Habitats and Water Habitats. Between the upper and lower epidermis is the epidermis. The inner cells of leaves (mesophyll) and stems also have air spaces among them, which help in the exchange of gases in the Internal Structure of a Leaf. The presence of pigment ‘chlorophyll’ makes the leaf green in color that helps to prepare food in plants through photosynthesis. The ultimate branches are very small and terminate in what are known as bundle ends. The epidermis is is also transparent and very thin to allow maximum light penetration. Every bundle is collateral with Xylem on the inner and phloem on the outer side. The petiole: It is the stalk-like structure which connects the leaf blade to the stem. The mesophyll is the region where the food making process called photosynthesis takes place. Stomata occur on both the epidermal layers. This website includes study notes, research papers, essays, articles and other allied information submitted by visitors like YOU. It is often differentiated into columnar palisade parenchyma on the adaxial side and irregular or isodiametric spongy parenchyma on this differentiation in mesophyll is referred to as dorsi­ventral, what is very common in dicotyledons. They form the protoderm by anticlinal division. A transverse section through a leaf of onion (Alliumcepa of family Liliaceae) would show the following internal structure (Fig. effectively. single layer of closely-packed cells. The bundles are collateral and closed ones with xylem and phloem. Leaves originate from the promeristem of the shoot apex. Bundle-ends vary considerably in the leaves, but com­monly it consists of a single tracheid with a single sieve element or specialised paren­chyma representing xylem and phloem respectively, surrounded by a parenchymatous bundle sheath (Fig. Xylem occurs on the adaxial and phloem on the abaxial sides. Xylem, as usual, consists of tracheary elements, and phloem of sieve tubes and companion cells. It is composed of more or less isodiametric cells with small inter­cellular spaces, thus the differentiation into palisade and spongy cells is absent. Feedback. The bundles remain arranged in a ring. Internal structure of a typical dicot stem shows following features: 1. During the Quiz End of Quiz. The outer layer of upper multiple epidermis and the lower epidermis as a whole are made of compactly-arranged tabular cells with cutinised outer walls having cuticle. Welcome to BiologyDiscussion! Below is a close diagram of the leaf structure: The basic structure of a leaf. The stomata close in the night to retain gases and moisture in the leaf cells and opens during the day for gaseous exchange to continue. Stomata: This lets in the gases the plants needs (Carbon Dioxide) and lets out the oxygen it produces. Though there may be considerable variations, the above is the general account of the development of a dicotyledonous leaf from the primordium, which may be represent­ed by the following scheme: Internal structures of a few common dorsiventral leaves are being described below: A thin section through the lamina of a leaf of mango (Mangifera indica of family Anacardiaceae) will show the following plan of arrangement of tissues (Fig. Diagram must be on 9 X 12 inch drawing paper. Patches of sclerenchyma occur more or less in parallel series towards both the upper and lower epidermis, as I-girders for withstanding shearing stress. mesophyll. They may, however, be regarded as water-storage tissues which do not possess chlorophyll. Some distinct cavities are present here and there. These are collateral and closed ones which remain arranged in parallel series. Using a microscope, it's possible toview and identify these cells and how they are arranged (epidermal cells,spongy cells etc). In case of bigger bundles bundle sheath extensions are present. Not all of the cells in the leaf have the "accessory" factor. The outer walls are cutinised and possess thin cuticle, the thickness being more pronounced in the cells of the upper epidermis than those on the lower side. These cells are located close to the leaf surface to maximise light absorption. Elongated sclerotic cells—the trichosclereids commonly called ‘internal hairs’, often with branched ends are frequently present. They remain surrounded by parenchymatous bundle sheath. Required fields are marked *. c) Palisade Mesophyll: Tightly packed upper layer of chloroplast containing cells. It is wavy in outline having distinct ridges and furrows and a large hollow cavity in the central regions. The meristematic cells occurring at the tip of the primordium constitutes the apical meristem of the leaf. It is mostly found above the ground and remains attached to the stem. Two or three layers of columnar cells with abundant chloroplasts remain arranged more or less at right angles to the upper epidermis. Their contact with conducting elements on one side and mesophyll on the other and often the extension up to epidermis are suggestive of positive physiological functions. A band of collenchyma, intercepted by chlorenchyma here and there, occurs next to epidermis forming the hypodermis. This band is referred to as bundle sheath or border parenchyma. Though a monocotyledon, the leaf of banana (Musa sapientum of family Musaceae) is dorsiventral. They are often differentiated into three layers—adaxial, abaxial and middle layers. After cessation of marginal growth further growth of the lamina is due to anticlinal division of the cells, so that surface area of the leaf is increased but in depth number of cell layers remain unchanged. A bigger bundle is composed of xylem and phloem, the former occurring to­wards upper epidermis and the latter towards the lower side. The leaf consists of three main sections: o The epidermis o The mesophyll o The vascular bundles 1. The first is to expose a maximum photosynthetic surface to sunlight; the second is to conserve water while, at the same time, providing for the exchange of gases necessary for photosynthesis. 613). Leaf structure. Plants must take in co2 from the atmosphere in order to photosynthesize. At the early stage of the development of the blade two strips of meristems, referred to as marginal meristem, occur along the two surfaces of the leaf axis. Multicellular hairs (trichomes) and stomata are found on epidermis. These subepidermal layers may be called special hypodermis. The spongy cells occurring towards lower epidermis are isodiametric, and often irregular in shape, and have profuse intercellular spaces. Xylem carries water from roots to the leaves. The large bundles have patches of heavily thick-walled sclerenchyma on the two edges, whereas the small bun­dles remain surrounded by sheath of parenchyma cells which have no chlorophyll. Leaf Structure and Function. On the adaxial side palisade cells occur in three or more layers forming a compact zone of columnar cells with little intercellular spaces. Privacy Policy3. Each stoma has an opening and two bean-shaped guard cells. These are palisade cells. Describes the structure and function of leaves. The number of chlo­roplasts is naturally much smaller here in comparison to palisade cells. In extreme cases the phloem may be absent and the veinlet may be made of a single spiral tracheid. Viewing the leaf under the microscope shows different typesof cells that serve various functions. They are the plant’s food factories. Every cell of the plant body exchanges gases with the environment on its own. A leaf is a plant organ that is flat, thin and usually green in color. Upper epidermis may be easily identified due to presence of large and empty bulliform cells. Whats people lookup in this blog: Leaf Internal Structure And Functions TOS4. Here stomata occur on both the epidermal layers, though they are more abundant on the abaxial side. Presence of conspicuous air spaces in the mesophyll is another marked feature. Considerable deposition of silicon is a distinctive character. Click Create Assignment to assign this modality to your LMS. You need to understand the structure of the tissues in a leaf together with their functions. The number of chloroplasts is naturally much smaller here, which explains the pale green colour of the lower surface of the leaf. Vascular bundles are very much reduced with very scanty mechanical elements and occur next to the palisade layer. Gases diffuse ion and out of the general surface of the young roots. Diagram must take up 80% of the sheet of paper. One with undifferentiated mesophyll, as commonly found in the monocotyledons, is known as an isobilateral leaf. The aquatic plants get the oxygen dissolved in water and release carbon dioxide in water. The gases are found in the soil surrounding the roots. Next to the epidermis occur a few layers, usually three, of collenchyma cells with thickened corners, forming the hypodermis. The spongy cells occur towards the lower epidermis. Draw a detailed diagram that shows the structure of a leaf 1. Under a powerful microscope, we can see three main internal parts of a leaf, i.e. As already stated, it is formed from an intercalary meristem located at the base of the finger-like protrusion of the shoot apex. A leaf is a compromise between two conflicting evolutionary pressures. It stops soon, and further expansion giving the leaf proper form is due to rapid enlargement by intercalary growth. The arrangement of veins in a leaf is called the venation pattern. It is composed of compactly-arranged cells, without showing any differentiation into palisade and spongy cells. It (Nymphaea stellata of family Nymphaeaceae) is characterised by the presence of large air chambers, peculiarly branched trichosclerieds or ‘internal hairs’ with calcium oxalate deposition, and irregularly scattered vascular bundles with extremely reduced xylem elements. Using an appropriately coloured crayon or felt-tip, mark in the structures on the diagram … '''Palisade Mesophyll''': Rod shaped cells that contain large numbers of chloroplasts for photosynthesis. A layer of parenchyma cells with scanty chlorophyll occurs just internal to both the epidermal layers. These are very much reduced. List the la ers of the leaf starting at the upper cuticle all the way to the … The leaf is the primary photosynthetic organ of the plant. The upper epidermis is multiseriate, being made of a few layer of cells. Thus the size of the bundle depends on the posi­tion one prefers to take while making a section. Identifying characteristics of the internal structure of dorsiventral or dicot leaf: (i) It is green, compressed with a wide lamina. Share Your Word File To do this a compound microscope is required given that itallows for higher magnification. The assessment will ask about the stomata and photosynthesis. Stomata are present on both the epidermal layers. Sequential Easy First Hard First. The conti­nuity of collenchyma is broken here and there by small patches of chlorophyll-containing parenchyma cells. The lower epidermis has many stomata. Play as. These leaves are common in the monocotyledons. They are of different types depending upon the type of edges, the pattern of the veins and the number of blades per leaf. Take a good look at the diagram and the various parts of the leaf structure… A big cavity is present in the central region. It is differentiated into palisade and spongy cells. Majority of the bundles are small, but fairly large bundles occur at regular intervals. Learn vocabulary, terms, and more with flashcards, games, and other study tools. % Progress . However, during the night when there is no photosynthesis occurring, the leaf cells get oxygen from the environment and release carbon dioxide through stomata. As an aquatic plant it has extremely reduced vascular and supporting tissues and well-formed air chambers. 623): It is uniseriate and continuous one, made of small round cells with strongly cuticularised outer walls. A section through a leaf of maize (Zea mays of family Graminaceae) shows the follow­ing structure (Fig. Small bundles have xylem on the upper and phloem on the lower sides surrounded by large parenchyma cells forming the bundle sheath. (iii) Mesophyll tissue is present and is composed of palisade parenchyma and spongy parenchyma. Each bundle has Xylem on the upper and phloem on the lower side. consists of one or two layers of closely-packed, long, cylindr…. Internal Leaf Structure a) Cuticle: Waxy layer water proofing upper leaves. The cells bordering the cavity are devoid of chloroplasts. Plants have no organs or systems for the exchange of gases with the environment. The rest of ground tissues is made of isodiametric parenchyma cells with distinct intercellular spaces. Like other organs they also exhibit three tissue systems (Fig. The bundles are collateral and closed ones which remain arranged in parallel series. A median procambium develops from the procambial strands of the shoot apex. It is single layerd and lack of chloroplast. Each stoma has an opening and two bean-shaped guard cells. Examples of anatomical changes in plants nerium leaf diagram structure things under a internal structure of leaf with diagram anatomy of leaf with diagram plant botany. The degree of cutinisation is more pronounced on the upper side. A transverse section through the petiole of Cucurbita would show the following structure (Fig. The arrangement of tissues in the petiole more or less resembles that of the stem. Obviously they are meant for providing mechanical strength against shearing stresses. They are composed of a few (usually three) layers of compactly-arranged isodiametric cells. Very commonly vascular bundles remain surrounded by a row of cells, which may or may not contain chloroplasts. The lower of the leaf is called the lower epidermis. Similarly, the carbon dioxide produced during cellular respiration is utilized in photosynthesis. A section through a succulent leaf with halophytic adaptations reveals the following structure (Fig. Different leaves have different margins. 622A): The epidermis is uniseriate made of compactly-arranged tabular cells with cuti­cularised outer walls. The bundles are of two types, viz., large and small ones. Inner palisade, i.e., palisade occurring on the abaxial side, is usually one- layered and consists of rather small cells. Learn vocabulary terms and more with flashcards games and other study tools. They develop as protrusions from the shoot apex and are organs of limited growth. The phloem elements are normally developed. Your email address will not be published. A few layers of columnar cells occur towards the adaxial side forming the palisade. epidermis, mesophyll, and vascular bundle. The ground tissue forming the mesophyll is differentiated into palisade and spongy cells. The structure of a leaf has adaptations so that it can carry out photosynthesis. The internal structure of a leaf diagram below is a cross section of a dicotyledonous leaf that shows all the different tissues that make up the leaf. Answer Now and help others. Patches of sclerenchyma occur on the upper and lower sides of the bundles. Occurrence of stomata and outgrowths are distinctive features. Calcium oxalate crys­tals are present here and there. Protection. Two types of tissues called xylem and phloem are present in the vascular bundle. A transverse section would reveal the following structure (Fig. The central part of the leaf is hollow. 615) more or less similar to the pre­vious one. A section through a leaf of datepalm (Phoenix sylvestris of family Palmae) would show the following structure (Fig. The outer layers of apical meristem just below the apex undergo anticlinal and periclinal divisions and give rise to a small rounded protrusion, what is the leaf primordium. A row of palisade parenchyma occurs next to epidermis forming more or less a compact band. Structure Of The Leaf | Plant | Biology | The FuseSchoolPlants make food through photosynthesis. There are two layers of palisade cells. It as usual forms the main bulk of the leaf, and is composed of iso­diametric cells with intercellular spaces. It is an effective mechanism for reducing transpiration. it is covered on the out…. 617): Both the adaxial and abaxial epidermal layers are multiseriate. The Structure of a Leaf By Cindy Grigg 1 The most numerous parts on most plants are their leaves. 2. Patches of collenchyma cells with thickened corners occur at the ridges. It is assumed that this layer serves as a temporary storage tissue, apart from-conducting the products of photosynthesis to the phloem. Moreover, there is deposition of waxy matters which prevents wetting and clogging of the stomata. A green pigment chlorophyll is present in chloroplasts. These cells markedly differ from the mesophyll. The petiole may continue into the midrib which bears branches and sub-branches ultimately rami­fying in the leaf lamina in both reticulate and parallel type of venation. palisade mesophyll. The bundle remains surrounded by a row of colourless parenchyma cells. Anatomy of leaf is the detailed study of internal structure of a leaf, usually revealed by its dissection. of family Graminaceae) would reveal the following internal structure (Fig. Questions. They are composed of closely-set cells. These leaves are acicular in shape and are more or less rounded in cross-section. Those on the upper side are larger in size. Explain its significance. 627): It is uniseriate, made of roundish cells with very scanty cuticularisation on the outer walls. Chloroplasts are abundantly pre­sent, usually along the radial walls of the cells. In some dicotyledons the bundle sheath extends up to the epidermis, either on one or on both sides of the leaf, and is termed bundle sheath extensions. The internal structure of a leaf: Leaves are very important structures. Each bun­dle remains surrounded by parenchymatous bundle sheath. Stomata occur on the lower epidermis. The leaf of oleander (Nerium oleander of family Apocynaceae) shows some distinct departures so far as the arrangement of tissues is concerned, from the ones described previously, exhibiting clear xerophytic adaptations. These are palisade cells. Petioles, stipules, veins, and a midrib are all essential structures of a leaf. Which organelle is known as “power house” of the cell? Chloroplasts are abundantly present. The central part of the mesophyll tissue is made of vascular bundles. These distinctly differ from the mesophyll. Here (Helianthus annus of family Compositae) it is grooved at one side and rounded at the other (fig.625). There are two types of bundles—small ones with one patch of phloem, and comparatively larger ones with two patches of phloem. The lower of the leaf is called the lower epidermis. The gaseous exchange between the internal photosynthetic tissues and outside atmosphere thus becomes easy. Start studying Diagram of internal structure of a leaf, Plant Tissues and Photosynthesis, Biology, Year 10 GCSEs. The spongy cells present towards lower epidermis and irregular in outline. Collectively, green … A section through the leaf of tuberose (Polianthes tuberosa of family Amaryllidaceae), would show the following anatomical structure (Fig. Stomata occur on the lower epidermis. Epidermal layers are uniseriate both on the adaxial and abaxial sides. The vascular tissues, in fact, form the skele­ton of the leaf, on which other tissues—the ground tissues, remain inserted. The lower epidermis is uniseriate. A leaf needs: a way to transport water to the leaf, and glucose. Fill it by the responses of the students and ask them to copy on their note books. The cells of the sheath contain plastids, often with starch grains. A large number of multicellular outgrowths are present. Thus the differentiation of mesophyll into palisade and spongy cells is absent; all the cells are of spongy type. Model 2 — Cross Section of the Internal Structure of a Leaf Cuticle Upper epidermis Chloroplast palisade mesophyll Air Space Lower epidermis Vein Spongy mesophyll Cuticle Guard cell f Stoma 8. This row made of parenchy­ma cells is referred to as bundle sheath or border parenchyma. Internal Structure of the Leaf of a Typical Dicotyledonous Plant. Parenchyma and often collenchyma cells are present on the outer and inner sides of the bundle which may reach up to the two epidermal layers. Internal Structure of Dicot Stems. Epidermis: Epidermis is the outermost layer of the stem. The vascular tissue system is composed of vascular bundles which are usually collateral and closed. Chlorophyll traps light energy which is used in the food-making process. Inner palisade, i.e., palisade occurring on the lower epidermis phloem of tubes! Microscope shows different typesof cells that serve various functions some bundles are poorly developed with chloroplasts... Draw a detailed diagram that shows the structure of the sheath contain starch, then it may be absent the... Mesophyll hardly shows differentiation between palisade and spongy cells is absent with branched ends are frequently present well-developed! Also exhibit three tissue systems ( Fig are isodiametric, much smaller here, which particularly occur the., teachers and general visitors for exchanging articles, answers and notes called venation! Cucurbita would show the following internal structure ( Fig waterlily ( Nymphaea stellata of family Moraceae would...: Dec 14, 2012 | Total Attempts: 5918, is usually layered. And worksheet to review and test Your understanding of the mesophyll does not differentiation... Ones here and there the upper and lower sides surrounded by large cells. Raw materials move across the leaf blade which is the stalk-like structure which connects leaf. Petioles, stipules, veins, and other study tools disclaimer Copyright, Share knowledge! Internal to epider­mis there are two types, viz., large and small ones tissue forming the bundle surrounded... The venation pattern conspicuous vacuoles and intercellular spaces, are formed lysigenously photosynthesize! 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