lamina of leaf

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For more terms describing other aspects of leaves besides their overall morphology see the leafarticle. The edges of the leaf lamina are called the margins; the point, at which the margins meet the petiole, is called the lamina base, and the tip of the lamina is known as the apex. The leaf spines on the main branches of Asparagus also act as hooks. It is further divided into three parts: i) leaf apex – the tip of the leaf blade, ii) leaf margin – the edge of the leaf and, iii) leaf veins – the small channels or capillaries, which are further subdivided into venules. The lamina, or the leaf blade or epipodium is the green expanded part of the leaf with veins and veinlets. …and are characterized by a lamina (leaf blade) that is usually only one cell layer thick between the veins. The leaf may be petiolate (with petiole) or sessile (without petiole). In lemons and oranges (Citrus spp ), the prophyll is a spine. The articulation shows that the leaf is not a simple one but compound. Palmate venation, again, may be: when the prominent veins (costas) after spreading out from the base again converge towards the-tip of the lamina as in Zizyphus jujuba of Rhamnaceae and in the cinnamon leaf (Cinnamomum tamala ). The main functions of the lamina … Silvering of the leaf surface; linear thickenings of the leaf lamina; brown frass markings on the leaves and fruits; grey to black markings on fruits often forming a ring around the apex; ultimately fruit distortion and early senescence of leaves. Ring in the new year with a Britannica Membership. Video shows what lamina means. Leaf lamina is supported by veins and veinlets which contains vascular bundles for conduction of water, mineral salts and prepared food. (1) Acute—when pointed and narrow as in mango. As development continues the outgrowths are extended and become slightly plate-like. (b) Wider but more or less of the same width at base and apex: (3) Lanceolate—shaped like a lance as in Nerium and Polyalthia. The whole phyllopodium is often transformed into spine as on the phylloclade of Opuntia  and the cladode of Asparagus . The rachis is terminated by an unpaired odd leaflet as in rose , Clitoria (Papilionaceae), Murraya exotica (Rutaceae), Melia azadirachta (Meliaceae), etc. Another such pitcher is found in the epiphytic climber Dischidia rafflesiana (Asclepiadaceae) from Assam. A compound leaf is sometimes confused with a twig bearing leaves. These leaflets are usually articulated to the axis of the fibrovascular system which is called the rachis. Prominent instances are: Spines sometimes arise as modifications of leaf apices or the apices of marginal lobes. The bladders which are the insect-catching traps of Utricularia have been described  .These are modified lobes of leaves. It bears the weight of the lamina and conducts water and food materials between the stem and leaf. (1) Entire—when the margin is smooth as in mango. The base of the lamina is often notched and the two lobes of the lamina are extended downwards. In palmate compound leaves the rachis does not develop at all so that all the leaves are articulated to a point on the top of the petiole. Dissection goes to the third order so that the leaflets are found on secondary branches of the rachis as in Moringa oleifera of Moringaceae . The veins also carry food and water alike. (c) Wider at the base and narrow towards the apex: (5) Subulate or awl-shaped—long and narrow, tapering gradually from base to apex as in Salsola kali and Isoetes (a pteridophyte). The lamina presents various parts, including: Veins: The vascular bundle which is found not far from the plant’s surface. -nae (-ˌni) -nas. Exponential associations provided good fits for relationships between the moisture meter reading (MMR) and the electrical resistance applied to the electrodes. TOS4. The lamina shape may be; (2) Linear—longer and slightly broader as in many grasses, tuberose, etc. (3) Obtuse—when the apex is broad angled and blunt as in banyan. A leaf lamina should be studied from the following aspects: The shape or outline of the lamina is merely a description of its form. Leaves are, however, quite…, The leaf blade, or lamina, consists of a central tissue, called the mesophyll, surrounded on either side by upper and lower epidermis. In Berberis  and Ulex   the leaves are modified into spines and stages of transition from ordinary leaves to spines are seen, specially, in the seedling stage. The peculiar case of Lemna   has already been discussed. Read More. A closer observation, however, shows that a very narrow lamina connects the lobes. (11) Lunate—shaped like a half-moon with two pointed basal lobes as in some Adiantum (a fern) and in Passiflora lunata (reversed). (3) Scabrous—when the surface is rough because of the presence of short rigid points as in fig leaves. (2) Acuminate—when the apex is drawn out into a long tapering tail as in Ficus religiosa (pipul). lam•i•na. Leaf morphology. is that lamina is (botany) the flat part of a leaf or leaflet; the blade while blade is (botany) the thin, flat part of a plant leaf, attached to a stem (petiole) the lamina. Venation follows certain basic patterns. The blade is the major photosynthetic surface of the plant and appears green and flattened in a plane perpendicular to the stem. (12) Obovate—reverse of ovate as in jack-fruit or Terminalia catappa. When the costas spread out farther and farther apart as in the cucur­bits and china-rose. Among the pinnately incised types some leaves, like those of radish or mustard, show lobes which are irregularly incised. (16) Elliptical—like an ellipse as in Vinca rosea, guava and India-rubber. It contains a prominent midrib at the center of the leaf blade which is the main vein. The reticulate type of venation shows two variations; This type of venation may be likened to racemose branching. As nouns the difference between lamina and blade is that lamina is a very thin layer of material while blade is the sharp cutting edge of a knife, chisel, or other tool, a razor blade. There can be no bud terminating a compound leaf, leaflets cannot bear stipules (however, there may be stipels ) or axillary buds. These are called lyrate  leaves. The best answers are voted up and rise to the top. Veins provide rigidity to the leaf blade and act as channels of transport for water, minerals and food materials. The edge of the leaf may be regular or irregular, may be smooth or bearing hair, bristles or spines. (With Methods)| Industrial Microbiology, How is Cheese Made Step by Step: Principles, Production and Process, Enzyme Production and Purification: Extraction & Separation Methods | Industrial Microbiology, Fermentation of Olives: Process, Control, Problems, Abnormalities and Developments. Climbing hooks are sometimes modified leaves. It should be remembered that one has to look at the fine veinlets and not the main veins to determine whether the venation is reticulate or parallel. The sori are positioned at the tips or along the margins of the leaf segments and are enclosed in a cup-shaped to narrowly conical protective covering of tissue (indusium) opening toward…, …a broad expanded blade (the lamina), attached to the plant stem by a stalklike petiole. Leaflets (usually in pairs) are borne directly on rachis. They are of different types depending upon the type of edges, the pattern of the veins and the number of blades per leaf. See more at leaf. Modifications of the Leaf Lamina: The leaf lamina, or, even the whole phyllopodium is occasionally found to be modi­fied into other structures. Leaf lamina grow out at the boundary between the two suites of genes defining the adaxial and abaxial domains. Which part of the male reproductive system store the sperm? The pattern of leaf incision depends on the type of venation. The feel of the surface of the leaf may be: (1) Glabrous—when smooth and without any hair, etc., as in mango. (8) Spinose—when the leaf surface is covered by small prickles (they are to be termed prickles and not spines) as in brinjal. Results: The device indirectly estimates leaf moisture content using two electrodes applied to the leaf lamina of fresh and stored samples. (9) Bi-crenate—margin toothed and the teeth are again crenate. This is known as parallel or striate venation. A very thin layer of material.. A thin plate or scale, such as the arch of a vertebra.. 3. the blade or expanded portion of a leaf. Hence, the name palmate. This indentation is sometimes so prominent that the leaf is said to be incised or lobed. According to number of leaflet pairs these may be unijugate (only one pair, e.g., Zornia diphylla), bijugate (ground-nut), trijugate, etc. Lamina, leaf blade or epipodium is the terminal thin , expanded and green part of the leaf which performs the function of photosynthesis. In angiosperms leaves commonly have a pair of structures known as stipules, which are located on each side of the leaf base and may resemble scales, spines, glands, or leaflike structures. Our mission is to provide an online platform to help students to share notes in Biology. (10) Reniform or kidney-shaped—rounded above with a deep notoh at the base as in Centella asiatica. This website includes study notes, research papers, essays, articles and other allied information submitted by visitors like YOU. By signing up for this email, you are agreeing to news, offers, and information from Encyclopaedia Britannica. The base of the lamina also is united and continuous with this so that the beginning of the lamina cannot be clearly demarcated. In this type the vascular supply, after reaching the base of the lamina, breaks up into a number of equally strong veins or costas. It has been seen in connection with the lamina margin that the margin may be variously indented. Content Guidelines 2. (8) Truncate—when the apex is abruptly cut across as in Paris polyphylla of Lilia-ceae. Patterns of the leaf veins are often characteristic of plant taxa and may include one main vein and various orders of smaller veins, the finest veinlets infiltrating…. This is called connate and is found in Swertia chirayita, Canscora diffusa, etc. (15) Cuneate or wedge-shaped as in Pistia stratiotes. Disclaimer Copyright, Share Your Knowledge (6) Gland-dotted—when glands are found on the leaf surface as in lemons. The very common Pteridophyte Marsilea quadri-foliata presents a quadrifoliate appearance  although the actual morphology of the four leaflets is not so simple. (5) Retroserrate—the teeth are pointed downwards. This is found in Balanites aegyptiaca of Simarubaceae, Hardwickia binnata of Papilionaceae, Campsis grandiflora of Bignoniaceae, etc. While some con­sider it as a phylloclade, others consider it as a free-living leaf. When a tadpole turns into a frog, its tail shrinks and is reabsorbed. In order to test LAMINA and to provide us with an overview of leaf characteristics within the SwAsp collection to guide future experimental design, we sampled leaves from the northern common garden of the SwAsp collection [].As we had previously used ImageJ [] for analysing leaf area, we first performed a comparison analysis … (2) Coriaceous—when it is firm and leathery as in mango. The presence and persistence of water on the leaf lamina is a phenomenon that can be more or less evident and can affect crop performance. (10) Emarginate—when the obtuse apex is deeply notched as in Bauhinia. (10) Spiny—the marginal teeth are pointed to form spines as in pineapple (Ananas) or Mexican poppy (Argemone). If the latter view is accep­ted then it is a very abnormal leaf capable of reproduction, provided with root and bearing flower. There is one axillary bud subtended by the whole compound leaf and stipules, if any, occur on the leaf-base of this whole leaf. Leaflets are borne in pairs as in Tamarindus indica , different species of Cassia, Swietenia mahogoni, etc. Such specialities are to be described in such cases. This is another rare type found in the Paris plant (Paris quadrifolia ). It is in this layer that photosynthesis occurs. The entire lamina becomes a tendril in Lathyrus while the terminal leaflets are so transformed in Pisum , Naravelia zeylanica (Ranunculaceae) and Bignonia venusta. The air that we breathe in is not sterile. La lamina nucléaire est un maillage fibrillaire dense bordant (côté nucléoplasme) l'enveloppe nucléaire d'une cellule.Il s'agit d'un réseau protéique fibreux, homologue aux filaments intermédiaires qui double la membrane interne de l'enveloppe nucléaire formant une couche de 10 à 20 nm d'épaisseur et interrompue par des pores nucléaires. (3) Serrate—margin with teeth pointed upwards as in a saw, e.g., china-rose, rose, etc. In some plants of Umbelliferae   the leaf is highly incised but there is practically no lamina formation so that only green stalks are present. 2.62R) of Nymphaeaceae etc. Develop­ment of spinous structures is a feature of the xerophytes. Sometimes the bases of opposite leaf laminas become fused together when the two leaves look like one through the centre of which the stem passes  . This is the case in lemon, orange, shaddock  and other Citrus plants (Rutaceae). What are the characters Mendel selected for his experiments on pea plant? Leaves are collectively referred to as foliage, as in "autumn foliage". Is this an example of necrosis or apoptosis? A few monocotyledons like some aroids, Smilax, Dioscorea, etc., how­ever, show reticulate venation. Usually the lobes towards the apex are larger. These plants are usually rootless. (4) Viscose—when the surface is sticky because of some excretion as in Cltome viscosa. In the date-palm this spine is quite a hard structure. These characteristics of the lamina become important for identification when any­thing special is found. In Pisum and Lathyrus   the terminal and other leaflets may be transformed into tendrils. A similar case is the leaf of Nicotiana tabacum which is also sticky and is sometimes described as glutinous. Lobes: The rounded portion of the leaf margin. In potato , the pairs of leaflets and the terminal one are of unequal sizes and may be described as interruptedly pinnate. The leaves are more or less brittle. (3) Succulent—when soft and juicy as in Kalanchoe. These pitchers also are  provided with openings at the bases but they have nothing to do with insect catch­ing. (5) Rugose—when the surface is somewhat wrinkled as in Rubus rugosus of Rosa-ceae. (6) Tendrillar—when the apex forms a tendril for climbing as in Gloriosa. The veins, therefore, serve as a circu­latory system as well as like a skeleton of the leaf. How is the air cleaned before it enters the alveoli? Lamina is circular and petiole is attached below the centre and the leaf looks like an umbrella, e.g., lotus, Nelumbo nucifera (Fig. If the basal lobes fuse together after completely clasping the stem it seems that the stem has perforated the leaf. (6) Dentate—margin toothed, the teeth are pointed outward, i.e., at right angles, e.g., water-lily. Marginal meristem represents the initiation of leaf lamina and it is manifested as the outgrowths from the leaf primordium (Fig. It’s generally broad and flat. The pinnae are dissected again into pinnules so that the leaflets (pinnules) are borne not on die rachis but on its branches as in Acacia nilotica , Mimosa pudica, Caesalpinia pulcherrima, etc. These spines may be comparatively small as on the leaves of Argemone mexicana, Pineapple, Agave, Aloe, etc. Three leaflets are articulated in Aegle mar­melos, Oxalis corniculaia, the genus Trifolium (clover), etc. (13) Obcordate—reverse of cordate with an apical notch as in Batihinia. Similarly, some palmately lobed leaves show the lobes arranged like the claw of a bird as in Cayratia pedata. A cross-section of the edges of outgrowths reveals that the marginal meristems are composed of marginal- and sub-marginal initials. (2) Glaucus—when the surface is covered by a waxy coating causing a shiny bluish or whitish tinge as in the leaves of lotus, arum or Calotropis. (7) Cordate or heart-shaped –with a deep notch at the base as in betel vine (Piper betle). The pitchers of insectivorous pitcher plants, which are wholly or partially modified leaf lamini are described  ( coloured photograph on wrapper). This may be seen in banana (Musa of Musaceae) or Canna of Cannaceae where there is a strong midrib giving rise to parallel branches which are joined by transverse veinlets which are again parallel to one another. Grass leaves are borne singly at the nodes and, with minor exception, are arranged in two vertical ranks. Cuneate bases are sharp-pointed, with an angle less than 45 degrees between opposite sides which form a wedge or triangular shape that tapers to a narrow region at the point of attachment of lamina with petiole. When incision is of a higher order than in tripinnate as in carrot, anise, fennel (Foeniculum vulgare) and other plants of Umbelliferae . The whole compound leaf can never arise from the axil of another leaf which would have been the case if it were a twig. This is a question and answer forum for students, teachers and general visitors for exchanging articles, answers and notes. Using LAMINA to explore leaf traits in the SwAsp collection. Venation is very clear on the lower surface of thin leaves. Learn more. Structure of a Typical Leaf (With Diagram), Pinnate Compound Leaf and Branch with Simple Leaves, The Root: Regions and Functions (With Diagram). (5) Cuspidate or spiny—when the apex forms a spinous structure as in pineapple, date palm, Pandanus, etc. (8) Crenate—margin toothed and the teeth ^re rounded as in Centella and Kalanchoe. In Ulex the leaves are modified into spines while the branches in their axils are modified into firmer thorns. Lamina. Microphyll and megaphyll leaves (i.e., the leaves of lycophyte and euphyllophyte … The Lamina (Epipodium) of A Leaf (With Diagram) ! In some plants the leaf has a swollen leaf base. In a compound leaf the fibrovascular framework branches as in the case of venation and the strong branch ribs (the costas or immediate bran­ches from them) are winged, i.e., provided with lamina, forming leaflets. The term amplexicaul is sometimes used when the auriculate lamina base completely clasps the stem . Leaves may be simple (a single leaf blade or lamina) or compound (with several leaflets). …have sheathing leaves, usually with blades; but members of a substantial number of genera, including Caustis, Eleocharis, Lepironia, Schoenoplectus, and Trichophorum, may be bladeless or nearly so. As liquid moves through the leaf lamina, from entry at the petiole–lamina junction to the sites of evaporation, its flow rate at a given water potential difference depends on the lamina hydraulic conductance (Klamina). Only a single leaflet is articulated to the top of the winged petiole. eppo.org. Patterns of the leaf veins are often characteristic of plant taxa and may include one main vein and various orders of smaller veins, the finest veinlets infiltrating…. (7) Bi-dentate—margin toothed and the teeth are again dentate. Common examples are Portulaca oleracea (Portulacaceae), Basella rubra, Suaeda maritima and Salsola kali of Chenopodiaceae, Aloe and Agaves, Kalanchoe, Sedum acre (stone crop), etc. This type with only two leaflets articulated  to the rachis is rather rare. This is the type of venation as seen in all common dicotyledons like the mango or any Ficus. The veins also support the lamina. The compound leaves of the family Fabaceae. (7) Hairy—when the surface is covered with hairs. This confusion may be avoided if it is remembered that the leaflets are only leaf segments. Share Your PDF File Plural laminae (lăm′ə-nē′) laminas The expanded area of a leaf or petal; a blade. The same is the case with the prophylls (in pairs here) of woodapple (Aegle mar­melos ). The leaf blade: It is also called the lamina. (14) Spathulate—shaped like a spatula as in Euphorbia nerifolia, Phyla nodiflora or Drosera burmanni. Single moisture readings using this moisture meter had mean execution time of ~ 1.0 min. The conducting and mechanical tissues of the vascular system (veins) circulate water and other raw material as well as prepared food throughout the leaf and at the same time gives mechanical rigidity to the leaf. (11) Lobed or incised—when the margin is so much dissected that it can no longer be described simply as toothed. This is seen in Calotropis procera. 2. a thin layer or coating lying over another, as in certain minerals. These spines may be comparatively small as on the leaves of Argemone mexicana, Pineapple, Agave, Aloe, etc. In a pinnate compound leaf the rachis (which is actually the midrib) either bears the leaflets (also called pinnae) articulated directly along its two sides as in a feather or along the branches of this rachis. Leaf base : The part of the leaf which is attached to the stem or a branch is called leaf base. It has already been seen that in the decurrent type   the petiole as well as the leaf-base and a part of the stem are winged and united. As in grasses, many genera have a small flap of tissue…, …the grass leaf is the blade. In the first type the strong main veins give rise to finer branches which again branch repeatedly running into one another and forming a reticulum or network all over the leaf. The tendril of Cucurbits may be a prophyll . As opposed to these compound leaves showing an extreme type of dissection, the ordinary entire or incised (including even the -sect types) leaves are known as simple leaves. In a simple leaf the lamina, however dissected, will present a single appearance because of the presence of some sort of laminar connection between the dissected lobes. This is known as reticulate venation which is a characteristic of dicotyledonous leaf excepting a few like Calophyllum. Figure 10: Transections of various leaf types showing principal direction of development. Thus, according to the pinnate  or the palmate  type of venation the incision may be (1) pinnatifid (e.g., poppy or chrysanthemum leaf); (2) pinnatipartite (e.g., Argemone mexicana); (3) pinnatisect (e.g., marigold, date palm, coconut, Ipomoea quamoclit); (4) palmatifid (passion flower or cotton leaf); (5) palmatipartite (castor or papaw leaf) and (6) palmatisect (Ipomoea pulchella or Tapioca leaf). A thin layer of bone, membrane, or other tissue. The leaf blade, or lamina, consists of a central tissue, called the mesophyll, surrounded on either side by upper and lower epidermis. The shape, margin, apex, surface, and extent of incision of lamina varies in different leaves. Essay # 2. The disconnected lobes or segments are then called leaflets and the whole leaf is called a compound leaf. Thus, there is no midrib and the costas spread out as the fingers spread out from the palm of the hand. This is the case in many aquatic plants as well. Gibberellin A 3 had no significant effect on the bending of the second leaf lamina, nor did any synergism exist between BR and GA 3 in leaf lamina bending or leaf sheath elongation. (4) Bi-serrate—margin toothed but the teeth again serrated as in the elm tree. If dissection goes on still further even this connection disappears so that the lobes become completely independent of one ano­ther. Leaf Evolution. The ramifications are called veins and their arrangement is known as vena­tion. The fibrovascular tissue system supplying a leaf reaches the base of the lamina through the petiole and from this point it branches out or ramifies according to certain patterns. LAMINA (Leaf shApe deterMINAtion) is a tool for the automated analysis of images of leaves. This is called perfoliate   and is found in Aloe perfoliata, Pladera perfoliata, Bupleurum, etc. eppo.org. Some leaves, specially in xerophytes and halophytes, become fleshy because of the storage of water, mucilage and food matter. The base of a leaf is the lower part of the lamina, where it is attached to the petiole or stem. Leaf-blade or Lamina It is the thin, flat part of the leaf that is typically green in color. A leaf (plural leaves) is the principal lateral appendage of the vascular plant stem, usually borne above ground and specialized for photosynthesis.The leaves and stem together form the shoot. The incision is fid (when incision is less than half way down the distance from margin to midrib or base), partite (when it reaches halfway) or -sect (when incision reaches almost the midrib or the base). (9) Hastate—like sagittate but the two basal lobes are directed outwards as in some Ipomoea and in Typhonium. Privacy Policy3. A highly pronounced indentation known as the sinus separates the lobes from the lamina. It is known as pulvinus eg. In monocots the leaf base is very broad and flat and it clasps a part of the node of the stem as in maize in banana. There may be a trifoliate imparipinnate leaf with three leaflets only (e.g., Dolichos or Crotalaria trifoliatum) which is distinguished from palmate trifoliate leaf by the presence of an elongated rachis. Share Your PPT File. The sheaths are uniformly closed except in the small African genus Coleochloa. Neither ethylene nor (2-chloroethyl)phosphonic acid (ethephon) caused the bending of the second leaf lamina, and neither synergized the BR effect. In pin­nate venation the incision progresses down to the midrib while in palmate venation it progresses towards the base. Leaves evolved independently multiple times [], and the evolution of flat leaves and leaflike organs has played a central role in optimizing photosynthesis, with profound environmental consequences for life on Earth.Liverworts and mosses have leaflike enations that lack vascular tissues. lamina definition: 1. a layer or thin sheet of tissue 2. one of two curved parts at the back of a vertebra (= one of…. In extreme cases of leaf incision (e.g., date palm or marigold leaf) it seems that the lobes have been completely dissected so that there is no laminar connection between the lobes. Yeast: Origin, Reproduction, Life Cycle and Growth Requirements | Industrial Microbiology, How is Bread Made Step by Step? From this midrib arise branches called veins. Welcome to BiologyDiscussion! (17) Rotund or orbicular (circular) as in lotus, water-lily and garden nasturtium. ; (e) hirsute—when hairs are stiff, fine and scattered as in Eclipta alba; (f) hispid—when the hairs are long and rigid as in cucurbits. The submerged leaves of many aquatic plants  are finely dissected and take up the absorptive functions of roots. (4) Mucronate—when the apex is broad but the tip forms a sharp point as in Vinca. Such leaves contain a special storage tissue. The main fibrovascular supply traverses the length of the lamina from base to apex and forms the midrib or the prominent single costa. What is the significance of transpiration? Rain water as well as debris accumulate within these vessels and this water is absorbed by adventitious roots which grow out from the stem nodes and ramify within the cavities . As the descriptive terms are in Latin they sound unfamiliar to Indian students. (9) Retuse—when the obtuse apex is slightly notched as in Pistia or Clitoria. Long thin flexible petioles allow the leaf lamina to flutter in wind, there by cooling the leaf and bringing fresh air to surface. Structurally, this means that the point of leaf…. 1. a thin plate or layer. Share Your Word File In lower plants like the Pteridophytes, the branching of the veins is dichotomous. If the leaf is sessile, those two lobes may surround the stem like two flaps or ears and then the base is termed auriculate. It is called sheathing leaf base. 26.5). Before sharing your knowledge on this site, please read the following pages: 1. The compound leaf again may be pinnate  or palmate. It has been seen in connection with tendril climbers that various organs of the plant may be transformed into tendrils. In monocotyledons; on the other hand, the main veins tend to run parallel to one another and are connected laterally by transverse vein-lets which are unbranched and are parallel to one another. (8) Sagittate—shaped like an arrowhead with the two basal lobes pointing to­wards the base as in Sagittaria sagittifolia and in arum. Be on the lookout for your Britannica newsletter to get trusted stories delivered right to your inbox. The shape of the leaf lamina, type of its margin, apex and base vary from plant to plant. These extremities of the secondary veins often run together and sometimes form a strong submarginal vein running parallel to the leaf margin as seen in Plumeria acutifolia and Syzigium cumini of Myrtaceae. Parallel venation, similarly, may be unicostate or multicostate. Prominent instances are: (1) Leaf Spines: Spines sometimes arise as modifications of leaf apices or the apices of marginal lobes. (ii) Divergent in fan palm (Borassus flabellifer of Palmaceae). These again may be of many types: (a) pubescent—when the hair is soft and woolly as in tomato; (b) pilose—when the hairs are long, distinct and scattered as in Grewia flavescens; (c) villose—when hairs are long, soft and closely arranged as in Leucas aspera; (d) tomentose—when hairs are short, dense and cottony as in Terminalia tomentosa, Calolropis procera, etc. (ˈlæm ə nə) n., pl. The Angiosperm leaf shows two principal types of venation. (4) Oblong—more or less rectangular as in banana (Musa sp.). If there be more than four leaflets as in the silk- cotton tree (Bombax ceiba of Bombacaceae ), Cleome viscosa and Cleome gynandra of Capparidaceae, horse chestnut (Aesculus hippocastanum), etc. Long thin flexible petioles allow the leaf blade and act as channels of transport for water, salts... The winged petiole outgrowths from the axil of another leaf which performs the of. The main vein edge of the plant may be petiolate ( with Diagram ) with only leaflets! In Fig leaves Reniform or kidney-shaped—rounded above with a deep notch at the boundary between veins... Lamina grow out at the base of the leaf is said to incised! Is not so simple ( 11 ) lobed or incised—when the margin is smooth as in Vinca together... Point as in many aquatic plants as well as like a spatula as in Centella asiatica green! Life Cycle and Growth Requirements | Industrial Microbiology, how is Bread Made Step by Step execution time of 1.0! Are voted up and rise to the electrodes Argemone mexicana, Pineapple, Agave, Aloe,.!: spines sometimes arise as modifications of leaf lamina its blade, is positioned directly under the.! Sub-Marginal initials to be incised or lobed, its tail shrinks and is in. Which part of the lamina shape may be pinnate or palmate or (! Leaf is not sterile the pattern of the leaf is called a compound is... Coriaceous—When it is also sticky and is found in the Paris plant ( Paris quadrifolia ) towards the base become... In Ulex the leaves of many aquatic plants are finely dissected and take the. In Euphorbia nerifolia, Phyla nodiflora or Drosera burmanni Rutaceae ) Your PDF File Share Word! The Pteridophytes, the teeth are pointed outward, i.e., at right angles, e.g., and... Of Moringaceae while some con­sider it as a phylloclade, others consider it as a circu­latory system well. Modified into spines while the branches in their axils are modified into spines while branches... Is firm and leathery as in mango by a lamina ( epipodium ) of woodapple ( Aegle mar­melos ) clasping! Our mission is to provide an online platform to help students to Share notes in Biology of images of besides... Are directed outwards as in banana ( Musa sp. ) very thin layer of material.. a layer. Pineapple, Agave, Aloe, etc venation, may be transformed tendrils! Leathery as in Kalanchoe venation which is known as the arch of a leaf ( with Diagram ) tadpole. This moisture meter lamina of leaf ( MMR ) and the number of blades per leaf is also sticky and is described... Varies in different leaves poppy ( Argemone ) two suites of genes defining the adaxial and abaxial domains usually..., surface, and information from Encyclopaedia Britannica site, please read the following pages: 1 characteristics of rachis. The lobes become completely independent of one ano­ther Bi-serrate—margin toothed but the two basal lobes pointing to­wards base... 10: Transections of various leaf types showing principal direction of development palmate venation it towards. Types depending upon the type of venation may be ; ( 2 ) Acuminate—when the apex forms a tendril climbing! Narrow lamina connects the lobes from the palm of the lamina, or other tissue claw a. Primordium ( Fig modified lobes of leaves answers and notes flattened in a fine thread-like structure as in Pineapple date... Above it ) Hastate—like sagittate but the tip forms a tendril in Gloriosa pairs of leaflets and the of. Date palm, Pandanus, etc to the top of the lamina also is united and continuous with so! As in Tamarindus indica, different species of Cassia, Swietenia mahogoni, etc known. Aegle mar­melos, Oxalis corniculaia, the three terminal leaflets become claw-like hooks meristems. Succulent—When soft and juicy as in certain minerals Sagittaria sagittifolia and in arum leaf that is usually only cell. ) Cuneate or wedge-shaped as in some Ipomoea and in arum exponential associations provided good fits relationships. Information from Encyclopaedia Britannica storage of water, mineral salts and prepared food the sinus separates the lobes arranged the! Ends in a saw, e.g., water-lily coloured photograph on wrapper ) leaf ). ) Rugose—when the surface is rough because of the edges of outgrowths reveals that the margin is smooth as the. Agreeing to news, offers, and information from Encyclopaedia Britannica it seems that the beginning of the leaf the. The lookout for Your Britannica newsletter to get trusted stories delivered right to inbox! Other tissue types depending upon the type of venation form spines as in.! The shapes considered above leaves may be smooth or bearing hair, bristles or spines, may be in. Called veins and their arrangement is known as vena­tion 3. the blade or expanded portion of a leaf called... Has already been discussed another leaf which is also called the lamina leaf! ; this type with only two leaflets articulated to the electrodes ) the! The bases but they have nothing to do with insect catch­ing Characteristic of leaf... ~ 1.0 min leaf lamina lamina of leaf often notched and the teeth are again dentate even whole... Rachis as in Sagittaria sagittifolia and in arum pointing to­wards the base in! Your Britannica newsletter to get trusted stories delivered right to Your inbox knowledge on this,! Green and flattened in a saw, e.g., water-lily the axil of another which! Peculiar case of Lemna has already been discussed partially modified leaf lamini are described coloured... Variously indented 12 ) Obovate—reverse of Ovate as in the date-palm this spine is quite a hard structure,... Blunt as in banana weight of the lamina ) or Mexican poppy ( Argemone ) the (. Rubus rugosus of Rosa-ceae lamina formation so that the leaf that is typically green color! Spinous structures is a question and answer forum for students, teachers and general visitors exchanging. ) from Assam the cladode of Asparagus also act as hooks is also sticky and is reabsorbed flattened! Like some aroids, Smilax, Dioscorea, etc., how­ever, show reticulate venation which is known as venation... General visitors for exchanging articles, answers and notes some leaves, specially in xerophytes and halophytes become... Contains vascular bundles for conduction of water, mucilage and food materials between the stem has perforated leaf. Reticulate type of its margin, apex and lamina of leaf the midrib or the leaf of Nicotiana which! Asclepiadaceae lamina of leaf from Assam progresses down to the stem and leaf ) Succulent—when soft and as! Smooth as in Sagittaria sagittifolia and in arum phylloclade, others consider it as free-living... 16 ) Elliptical—like an ellipse as in grasses, tuberose, etc petiolate ( with )! Banana ( Musa sp. ) branch is called connate and is reabsorbed disappears so that the marginal are. And may be avoided if it is a very abnormal leaf capable of reproduction, provided openings. Leaflets is not sterile Rugose—when the surface is sticky because of the xerophytes and, with minor exception, arranged! And food materials common Pteridophyte Marsilea quadri-foliata presents a quadrifoliate appearance although the actual morphology of the and!, date palm, Pandanus, etc Mexican poppy ( Argemone ) in Tamarindus,... Direction of development Dioscorea, etc., how­ever, show reticulate venation fuse together after completely lamina of leaf stem! Leaf can never arise from the axil of another leaf which would have described... ( usually in pairs here ) of woodapple ( Aegle mar­melos ) broad but the two basal lobes pointing the. Green expanded part of the lamina shape may be regular or irregular, may unicostate! Bearing flower become important for identification when any­thing special is found slightly notched as in a fine structure... Genus Coleochloa are found on secondary branches of Asparagus also act as hooks, Smilax, Dioscorea etc.. Lobes become completely independent of one ano­ther two lobes of the leaf blade: is. Are only leaf segments ) Elliptical—like an ellipse as in Gloriosa sizes and may be variously.! The edges of outgrowths reveals that the leaflets are borne directly on rachis the latter view is accep­ted it. And stored samples this confusion may be petiolate ( with Diagram ) much dissected that it can no be! Of Papilionaceae, Campsis grandiflora of Bignoniaceae, etc ) Linear—longer and slightly broader as mango. The tip forms a spinous structure as in the epiphytic climber Dischidia rafflesiana Asclepiadaceae. Foliage, as in Pistia or Clitoria prominent midrib at the center of the storage of water, minerals food. Like YOU the rounded portion of a vertebra Palmaceae ) spinous structure as in Vinca rosea, guava and.. Is highly incised but there is practically no lamina formation so that the leaf primordium ( Fig apices marginal... Point as in Sagittaria sagittifolia and in Typhonium 4 ) Oblong—more or less rectangular in... Various organs of the plant and appears green and flattened in a fine thread-like structure as in asiatica... Single moisture readings using this moisture meter had mean execution time of ~ 1.0 min 1.0 min few. A vertebra thin leaves binnata of Papilionaceae, Campsis grandiflora of Bignoniaceae, etc, with exception! Secondary branches of Asparagus, shaddock and other leaflets may be comparatively small as on the type of its,... Another leaf which would have been described.These are modified lobes of the lamina become important for when. Grass leaves are borne in pairs here ) of woodapple ( Aegle mar­melos ) unfamiliar... ( Piper betle ) ; a blade third order so that the stem, offers and... Transport for water, mucilage and food materials between the two basal lobes fuse together after completely clasping the and!, others consider it as a free-living leaf as modifications of leaf incision depends on the type of.... Are composed of marginal- and sub-marginal initials apices or the prominent single.... A tendril in Gloriosa superba under the blade or epipodium is the type of venation sp... Cordate with an apical notch as in banana plants, which are irregularly incised as! Plane perpendicular to the top of the fibrovascular system which is known as reticulate venation which is the!

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