lamina of leaf

This is called connate and is found in Swertia chirayita, Canscora diffusa, etc. Typically, a leaf consists of a broad expanded blade (the lamina), attached to the plant stem by a stalklike petiole.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 … (9) Hastate—like sagittate but the two basal lobes are directed outwards as in some Ipomoea and in Typhonium. These are called pedate  leaves. The lamina presents various parts, including: Veins: The vascular bundle which is found not far from the plant’s surface. It has been seen in connection with tendril climbers that various organs of the plant may be transformed into tendrils. Among the pinnately incised types some leaves, like those of radish or mustard, show lobes which are irregularly incised. 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 . The lamina, or the leaf blade or epipodium is the green expanded part of the leaf with veins and veinlets. https://www.britannica.com/science/lamina-plant-leaf, Cyperaceae: Characteristic morphological features, Poaceae: Characteristic morphological features. Another such pitcher is found in the epiphytic climber Dischidia rafflesiana (Asclepiadaceae) from Assam. A closer observation, however, shows that a very narrow lamina connects the lobes. (5) Retroserrate—the teeth are pointed downwards. These plants are usually rootless. Neither ethylene nor (2-chloroethyl)phosphonic acid (ethephon) caused the bending of the second leaf lamina, and neither synergized the BR effect. (7) Cirrhose—when the mucronate-like apex ends in a fine thread-like structure as in banana. The tendril of Cucurbits may be a prophyll . In lower plants like the Pteridophytes, the branching of the veins is dichotomous. A compound leaf, just like venation, may be pinnate or palmate. eppo.org. As in grasses, many genera have a small flap of tissue…, …the grass leaf is the blade. 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 Lamina (Epipodium) of A Leaf (With Diagram) ! 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. (11) Lobed or incised—when the margin is so much dissected that it can no longer be described simply as toothed. Some leaves, specially in xerophytes and halophytes, become fleshy because of the storage of water, mucilage and food matter. A very thin layer of material.. A thin plate or scale, such as the arch of a vertebra.. There is, usually, a middle prominent vein, which is known as the midrib. Thus, there is no midrib and the costas spread out as the fingers spread out from the palm of the hand. [1650–60; < Latin lāmina] (1) Entire—when the margin is smooth as in mango. (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). (6) Dentate—margin toothed, the teeth are pointed outward, i.e., at right angles, e.g., water-lily. What are the characters Mendel selected for his experiments on pea plant? (3) Succulent—when soft and juicy as in Kalanchoe. It is in this layer that photosynthesis occurs. (7) Bi-dentate—margin toothed and the teeth are again dentate. 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 ). 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. 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. 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. When incision is of a higher order than in tripinnate as in carrot, anise, fennel (Foeniculum vulgare) and other plants of Umbelliferae . The main fibrovascular supply traverses the length of the lamina from base to apex and forms the midrib or the prominent single costa. 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. A few monocotyledons like some aroids, Smilax, Dioscorea, etc., how­ever, show reticulate venation. 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. Usually the lobes towards the apex are larger. Share Your PDF File It bears the weight of the lamina and conducts water and food materials between the stem and leaf. The reticulate type of venation shows two variations; This type of venation may be likened to racemose branching. 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  . 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. In the date-palm this spine is quite a hard structure. Similarly, some palmately lobed leaves show the lobes arranged like the claw of a bird as in Cayratia pedata. Plural laminae (lăm′ə-nē′) laminas The expanded area of a leaf or petal; a blade. The leaf lamina, or, even the whole phyllopodium is occasionally found to be modi­fied into other structures. It is called sheathing leaf base. Veins provide rigidity to the leaf blade and act as channels of transport for water, minerals and food materials. In this type the vascular supply, after reaching the base of the lamina, breaks up into a number of equally strong veins or costas. 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