Hairy stipules : These are hair like stipules which are dry in nature, e.g., Anacampsora. In monocotyledons, the leaf base expands into a sheath covering the stem partially or wholly. e.g., Moringa (Soanjana) and Millingonia. Each spiral is called the genetic spiral. e.g., Jamun, Guava, etc. (iv) Habitual heterophylly : Leaves of different shape and incisions occur at the same time, e.g., Jack fruit tree (Artocarpus heterophyllus), Ficus heterophylla, Hemiphragma heterophyllum, Broussonetia papyrifera. (iii) Lamina (Epipodium) : The green expanded portion of the leaf is called the lamina. Winged petiole : Green, flattened petioles may be called winged petioles, e.g., Citrus and Dionaea. Tutor log in |
Pulvinus is a swollen leaf base. (7) Modification of leaves : Some important leaf modification are as follows : (i) Leaf tendrils : In many weak stemmed plants, the leaves are modified into slender wiry and coiled structures called leaf tendrils. Glabrous : Smooth and without hair. Such leaves are called storage leaves. Create your Smart Home App in the Free Webinar on Home Automation. In Citrus first leaf of axillary branch modified in to spine. The single leaflet is articulated to the top of petiole, e.g., Citrus (Khatta), Lemon, etc. The Isoetaceae are distinctive in being cormose to rhizomatous plants with a basal rosette of microphyllous, ligulate leaves, the leaves basally sheathing, apically linear to acicular, heterosporous, bearing adaxial megasporangia or microsporangia within sheathing leaf base. indicated by arrows, and the same stage is also seen in Fig. The leaf consists of three parts namely, leaf base (usually provided with a pair of stipules), petiole and leaf blade or lamina. Leaf like petiole (Phyllode) : A modified petiole which is flat, green and lamina like is called phyllode. 1A. using askIItians. Register Now. 150–500 µm wide; linear, with bistratose lamina. e.g,. Leaf sheath definition at Dictionary.com, a free online dictionary with pronunciation, synonyms and translation. In a simple leaf, such as the banana leaf, the blade is completely undivided. Leaves with stipules are called stipulate and those without them are called exstipulate. Spinous : In some plants the stipules are modified into hard, pointed defensive organs called spines, e.g., Acacia arabica, Prosopis juliflora and Zizyphus. e.g., Neem, Rose, Murraya. The ZIP System is a structural sheathing intended for walls and roofs, with an OSB base and WRB (weather resistive membrane), which is basically a mesh that is attached to an OSB sheathing panel with a paint applied. Microtome sections through the leaf-buds of Hydrocharis Morsus-ranae , L., show that the orbicular floating leaves are sheathing at the base (Fig. It is a hydrophytic adaptation e.g., Trapa bispinosa and Eichhornia. Sheath pronounced as /ʃiːθ/, may refer to: Scabbard, a sheath for holding a sword, knife, or other large blade, as well as guns, such as rifles. Note the large leaf on the stem with its inflated base. Entries with "sheathing" sheath: …A condom. Leaf base contain 2 lateral outgrowth called stipules & leaf containing them is called stipulate leaf. The sheathing base and the pulvinus have however been described by these authors as modified leaf-bases. (vi) The leaves do not possess any apical bud or a regular growing point. Questions Exercise - 1 1. name, Please Enter the valid e.g., Sorghum, Wheat and Palms. Fig. The simple leaf may be entire (e.g., Mango and Hibiscus rosa sinensis) or lobed. In addition, there are transitional leaf forms with reduced blades, culminating in bladeless bud … The base of a leaf when sheathing or investing a stem or branch, as in grasses. This sheathing leaf base is of frequent occurrence among monocotyledons. - The leaf is a green, flat, thin, expanded lateral appendage of stem which is borne at a node and bears a bud in its axil. dogs and horses. e.g., Clitoria. grade, Please choose the valid Leaf blade much narrower than sheathing base, ca. Succulent : When the lamina is thick, soft and juicy. Petiole or leaf stalk is a cylindrical or subcylindrical or flattened structure of a leaf which joins the lamina … (A–C) Projection of the vascularized stipules as a pair laterally to the petiole. Leaf base not sheathing but stipules present, occasionally ± fused distal to node Position on a stem from which one or more structures (especially leaves, buds, branches, or flowers) arise. 2 H, drawn from another leaf. Adnate stipules : The two stipules that fuse with the leaf base or petiole on either side are called adnate stipules, e.g., Arachis and Rose. Sitemap |
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It is a photosynthetic organ. sheathing leaf base is formed in which the right and left margins overlap from their very inception, not simply as a result of post-primordial, lateral growth. The leaf shape may also be formed of lobes where the gaps between lobes do not reach to the main vein. It is seen in Fabaceae family. Today, we still eat the wheat berry but unlike 17,000 years ago, we eat a refined product of wheat … Hulled Wheats. Interestingly, in some species such as D. terrestre and D. rigidifolium the short free leaf bases that can be seen below the abscission layer … Quadrifoliate : This leaf has four leaflets attached to the tip of petiole. Spinose : Covered with small spines. Name and define the two types of leaf morphology in … Leaf base not sheathing but stipules present, occasionally ± fused distal to node when leaves opposite 3. Sometimes, small stipule like outgrowths are found at the base of leaflets of a compound leaf. It raises the lamina above the level of stem so as to provide it with sufficient light exposure. (ii) Environmental heterophylly : The heterophylly is due to change in environment including soil, temperature, humidity and air currents. In Phoenix leaf tip modified into spine. - It is exogenous in origin and develops from the leaf primordium of shoot apex. Hispid : Covered with long rigid hair. ZIP Sheathing is a pretty hot topic with some differing opinions. Such swollen leaf bases are called pulvinate leaf bases as seen in mango leaves. 3. They are borne in pairs. (ii) Petiole (Mesopodium) : A petiole or leaf stalk is a cylindrical or sub cylindrical structure of a leaf which joins the lamina to the base. Entries with "sheathing" sheath: …A condom. e.g., Solanum xanthocarpum. The following examples are all simple leaves. (i) Simple leaves : The leaf having single undivided lamina is called the simple leaf. (E) Fusion of the sheathing stipules of a node. A leaf gap is an area along the stem where phloem and xylem diverge from the ... veined leaves with clasping/sheathing leaf bases. The leaf is attached to the stem by the leaf base (hypo-podium) and may bear two lateral small leaf-like structures called stipules. They are classified as follows : Foliaceous : Green, expanded, leaf like stipules are called foliaceous stipules. Bael), Oxalis corniculata, Trifollium (Clover), etc. (5) Vernation : Arrangement of leaves in bud condition is known as vernation imbricate (irregular overlapping), contorted (twisted, regular overlapping of margins), induplicate (margin bent inwardly), equitant (conduplicate in two series, one overlapping the other completely), half equitant, supervolute (convolute leaves, one rolled over other). The leaflets may be arranged alternately or in pairs along with the rachis. Such modified leaves are called absorbing leaves. 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