(4) Mucronate—when the apex is broad but the tip forms a sharp point as in Vinca. 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). Dicot leaf primordia initiate at the flanks of the shoot apical meristem and extend laterally by cell division and cell expansion to form the flat lamina, but the molecular mechanism of lamina outgrowth remains unclear. Our mission is to provide an online platform to help students to share notes in Biology. 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). (4) Oblong—more or less rectangular as in banana (Musa sp.). 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. (iv) It is exogenous in originand develops from the swollen leaf primordium of the growing apex. The appearance of leaves with flattened laminae about 400 million years (Myr) ago had broad impacts on the Earth’s ecosystem. What are the general characters of bryophytes? Name the types of nitrogenous bases present in the RNA. (4) Gland-dotted—the presence and nature of glands (e.g., on lemon leaves) may be considered in connection with texture as well as in connection with lamina surface. In a… Figure 10: Transections of various leaf types showing principal direction of development. The very common Pteridophyte Marsilea quadri-foliata presents a quadrifoliate appearance although the actual morphology of the four leaflets is not so simple. The sheath is a structure, typically at the base that fully or partially clasps the stemabove the node, where the latter i… (7) Bi-dentate—margin toothed and the teeth are again dentate. (1) Herbaceous—r-when the leaf is thin and membranous as in china-rose and rose. These are called lyrate leaves. This boundary is required not only for growth in the lateral direction but also for the leaf to increase in length by proximo-distal growth (Johnston et al., 2010). Among the pinnately incised types some leaves, like those of radish or mustard, show lobes which are irregularly incised. This is a question and answer forum for students, teachers and general visitors for exchanging articles, answers and notes. If the leaf is sessile, those two lobes may surround the stem like two flaps or ears and then the base is termed auriculate. (5) Retroserrate—the teeth are pointed downwards. The expanded area of a leaf or petal; a blade. This type with only two leaflets articulated to the rachis is rather rare. This is seen in Calotropis procera. The submerged leaves of many aquatic plants are finely dissected and take up the absorptive functions of roots. (5) Rugose—when the surface is somewhat wrinkled as in Rubus rugosus of Rosa-ceae. The secondary veins often do not reach the margin but before reaching the edge either fizzle out or curve and run parallel to the margin for a short length. Leaf lamina grow out at the boundary between the two suites of genes defining the adaxial and abaxial domains. 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…. 4. Stem: part of the plant that carries the leaves. These are called pedate leaves. What is a mushroom shaped gland? Botánica Leaf, una preciosa lámina decorativa con un sutil dibujo de estilo botánico, ideal para decorar tus estancias y conseguir un estilo romántico y con mucha serenidad. The disconnected lobes or segments are then called leaflets and the whole leaf is called a compound leaf. (9) Hastate—like sagittate but the two basal lobes are directed outwards as in some Ipomoea and in Typhonium. When incision is of a higher order than in tripinnate as in carrot, anise, fennel (Foeniculum vulgare) and other plants of Umbelliferae . 1. a thin plate or layer. (9) Bi-crenate—margin toothed and the teeth are again crenate. In Macfadena unguiscati from Assam, the three terminal leaflets become claw-like hooks . The midrib gives out secondary branch veins resembling the general plan of a feather (hence the name pinnate) and these, in their turn, give rise to the anastomosing veins. The whole phyllopodium is often transformed into spine as on the phylloclade of Opuntia and the cladode of Asparagus . https://www.britannica.com/science/lamina-plant-leaf, Cyperaceae: Characteristic morphological features, Poaceae: Characteristic morphological features. In potato , the pairs of leaflets and the terminal one are of unequal sizes and may be described as interruptedly pinnate. Lamina of the vertebral arch; Planar lamina, a two-dimensional planar closed surface with mass and density, in mathematics; Lamina face, a face sharing all edges, in computer graphics; A thin plate, sheet or layer, such as: Lamina (algae), a structure in seaweeds Basal lamina, a structure of a living cell; Nuclear lamina, another structure of a living cell Besides the shapes considered above leaves may be shaped differently by incision of the leaf lamina. [1650–60; < Latin lāmina] A compound leaf is sometimes confused with a twig bearing leaves. Muchos ejemplos de oraciones traducidas contienen “lámina” – Diccionario inglés-español y buscador de traducciones en inglés. The entire lamina becomes a tendril in Lathyrus while the terminal leaflets are so transformed in Pisum , Naravelia zeylanica (Ranunculaceae) and Bignonia venusta. The Angiosperm leaf shows two principal types of venation. -nae (-ˌni) -nas. Photograph taken in the botanical garden of Munich, Bavaria, Germany. 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. (3) Succulent—when soft and juicy as in Kalanchoe. The thinnest recognizable layer of sediment, differing from … The articulation shows that the leaf is not a simple one but compound. Compre Lámina de plástico, Transparente, 1250mm x 610mm x 2mm Láminas de Plástico en RS Online y disfrute de una entrega en 24 h, un excelente servicio y el mejor precio del distribuidor líder en componentes electrónicos This indentation is sometimes so prominent that the leaf is said to be incised or lobed. (10) Emarginate—when the obtuse apex is deeply notched as in Bauhinia. Not every species produces leaves with all of these structural components. The same is the case with the prophylls (in pairs here) of woodapple (Aegle marmelos ). …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. 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. A similar case is the leaf of Nicotiana tabacum which is also sticky and is sometimes described as glutinous. Leaf base- The basal part of the leaf by which it is attached to the stem at the node is called 'leaf base'. The lamina is the expanded, flat component of the leaf which contains the chloroplasts. Te queremos dar las mejores opciones para darle a esas paredes vacías mucha vida. Grass leaves are borne singly at the nodes and, with minor exception, are arranged in two vertical ranks. II. In lower plants like the Pteridophytes, the branching of the veins is dichotomous. If the basal lobes fuse together after completely clasping the stem it seems that the stem has perforated the leaf. 3. the blade or expanded portion of a leaf. It is the stalk by which the leaf lamina is attached to the main stem. 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. Before sharing your knowledge on this site, please read the following pages: 1. Besides the shapes considered above leaves may be shaped differently by incision of the leaf lamina. The ramifications are called veins and their arrangement is known as venation. Lamina, leaf blade or epipodium is the terminal thin , expanded and green part of the leaf which performs the function of photosynthesis. 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 bladders which are the insect-catching traps of Utricularia have been described .These are modified lobes of leaves. Some leaves, specially in xerophytes and halophytes, become fleshy because of the storage of water, mucilage and food matter. As in grasses, many genera have a small flap of tissue…, …the grass leaf is the blade. In the date-palm this spine is quite a hard structure. Contact me- https://instagram.com/harharmhadev786?igshid=1md12wd0lmrtt B.Sc. The whole compound leaf can never arise from the axil of another leaf which would have been the case if it were a twig. Structurally, this means that the point of leaf…. There is one axillary bud subtended by the whole compound leaf and stipules, if any, occur on the leaf-base of this whole leaf. By signing up for this email, you are agreeing to news, offers, and information from Encyclopaedia Britannica. Hence, the name palmate. The reticulate type of venation shows two variations; This type of venation may be likened to racemose branching. The compound leaf again may be pinnate or palmate. In this type the vascular supply, after reaching the base of the lamina, breaks up into a number of equally strong veins or costas. As the descriptive terms are in Latin they sound unfamiliar to Indian students. Yeast: Origin, Reproduction, Life Cycle and Growth Requirements | Industrial Microbiology, How is Bread Made Step by Step? (7) Hairy—when the surface is covered with hairs. (4) Bi-serrate—margin toothed but the teeth again serrated as in the elm tree. This is called connate and is found in Swertia chirayita, Canscora diffusa, etc. This is the case in many aquatic plants as well. (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. (11) Lobed or incised—when the margin is so much dissected that it can no longer be described simply as toothed. Lamina of the leaf (Blade) [ Botany] The lamina is the expanded portion or blade of a leaf and it is an above-ground organ specialized for photosynthesis.For this purpose, a leaf is typically, to a greater or lesser degree, flat and thin, to expose the chloroplast containing cells (chlorenchyma) to light over a broad area, and to allow light to penetrate fully into the tissues. Midrib-The petiole enters into the lamina of the leaf and continues as the mid rib. (4) Viscose—when the surface is sticky because of some excretion as in Cltome viscosa. Similarly, some palmately lobed leaves show the lobes arranged like the claw of a bird as in Cayratia pedata. The veins, therefore, serve as a circulatory system as well as like a skeleton of the leaf. Essay # 1. A typical leaf of two main parts: an expanded blade or lamina, and a stalk called the petiole, by which the leaf is attached to the stem. (vii) A leaf has three main parts – Leaf base, petiole and leaf lamina. ADVERTISEMENTS: Here is an essay on the ‘Lamina of a Leaf’ for class 9, 10, 11 and 12. The base of the lamina also is united and continuous with this so that the beginning of the lamina cannot be clearly demarcated. 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. 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). What is its function? (1) Entire—when the margin is smooth as in mango. 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. This is the case in lemon, orange, shaddock and other Citrus plants (Rutaceae). Results. (v) The growth of leaf is limited. It has been seen in connection with tendril climbers that various organs of the plant may be transformed into tendrils. (2) Coriaceous—when it is firm and leathery as in mango. Thus, a leaf, and most conspicuously its blade, is positioned directly under the blade two nodes above it. 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. Where are the pollen grains formed in the flower? This is called perfoliate and is found in Aloe perfoliata, Pladera perfoliata, Bupleurum, etc. The leaves are more or less brittle. 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. 2. a thin layer or coating lying over another, as in certain minerals. (6) Ovate or egg-shaped—as in china-rose and banyan. (iii) Generally there is always an axillary budin the axil of a leaf. Leaflets are borne in pairs as in Tamarindus indica , different species of Cassia, Swietenia mahogoni, etc. (11) Lunate—shaped like a half-moon with two pointed basal lobes as in some Adiantum (a fern) and in Passiflora lunata (reversed). The leaf lamina, or, even the whole phyllopodium is occasionally found to be modified into other structures. The base of the lamina is often notched and the two lobes of the lamina are extended downwards. (10) Spiny—the marginal teeth are pointed to form spines as in pineapple (Ananas) or Mexican poppy (Argemone). These are […] (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. The Lamina (Epipodium) of A Leaf (With Diagram) ! lamina stock pictures, royalty-free photos & images Prominent instances are: Spines sometimes arise as modifications of leaf apices or the apices of marginal lobes. What is the world's most endangered animal? Shoeing a number of strong veins (costas) which are. The proximal stalk or petiole is called a stipe in ferns. Read More. (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. Parallel venation, similarly, may be unicostate or multicostate. These spines may be comparatively small as on the leaves of Argemone mexicana, Pineapple, Agave, Aloe, etc. (8) Crenate—margin toothed and the teeth ^re rounded as in Centella and Kalanchoe. (vi) The leaves do not possess any apical bud or a regular growing point. Answer Now and help others. (8) Sagittate—shaped like an arrowhead with the two basal lobes pointing towards the base as in Sagittaria sagittifolia and in arum. Plural laminae (lăm′ə-nē′) laminas. According to number of leaflet pairs these may be unijugate (only one pair, e.g., Zornia diphylla), bijugate (ground-nut), trijugate, etc. 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 . 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. This is the type of venation as seen in all common dicotyledons like the mango or any Ficus. Sutileza y serenidad. The peculiar case of Lemna has already been discussed. Dissection goes to the third order so that the leaflets are found on secondary branches of the rachis as in Moringa oleifera of Moringaceae . This is found in Balanites aegyptiaca of Simarubaceae, Hardwickia binnata of Papilionaceae, Campsis grandiflora of Bignoniaceae, etc. (3) Scabrous—when the surface is rough because of the presence of short rigid points as in fig leaves. 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. Here, we report the identification of STENOFOLIA (STF), a WUSCHEL-like homeobox … (ii) A leaf is always borne at the node of stem. Share Your Word File Such specialities are to be described in such cases. (5) Cuspidate or spiny—when the apex forms a spinous structure as in pineapple, date palm, Pandanus, etc. 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. lamina" a blade or a thin plate ] Any thin, flat layer or sheet of membrane or other tissue. Dar las mejores opciones para darle a esas paredes vacías mucha vida like some aroids Smilax! Unfamiliar to Indian students direction of development before sharing Your knowledge on this site, please read the following:. 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