Lab 5 Morphology PDF

Welcome to Pharmacognosy Department Lab. 5 Introduction of leaves I- Morphology  Leaf Leaf: Lateral outgrowth from the stem. Leaf apex Leaf margin Consists of three par...

Welcome to Pharmacognosy Department Lab. 5 Introduction of leaves I- Morphology  Leaf Leaf: Lateral outgrowth from the stem. Leaf apex Leaf margin Consists of three parts: Leaf lamina Leaf petiole Bud Leaf base Vennation Midrib Leaf lamina Leaf petiole Leaf base  Scheme for description of Leaf morphology Aim: to be able to describe the leaves on scientific bases  Scheme for description of Leaf morphology - Fresh or dry 1. Condition: - Entire or broken pieces 2. Colour: As seen  3. Insertion Cauline Radical Leaves are arranged Leaves are arranged on elongated stem on a discoid stem crowded on top of root eg: Carrot.  4. Phyllotaxis Arrangement of leaves on the elongated stem Alternate or spiral Opposite One leaf on each node Two leaves on the same node opposite to each other  Opposite decussate Whorled or verticillate Two leaves opposite Three or more leaves each pair is perpendicular on each node to the pair above and below  5. Leaf base or phyllopodium a. Stipules b. Sheath a. Stipules Lateral projection at the leaf base For protection of the axillary bud May be hairy, leafy or spiny Present Absent Stipulate Exstipulate  Stipules Leafy Spiny b. Sheath  6. Leaf petiole a. Occurrence b. Characters c. Pulvinous a. Occurrence Petiolate Sessile  b. Characters Short Long petiole  Colour Green purple Shape: Cylindrical, quadrangular, flattened Cylindrical flattened  surface Glabrous Pubescent (To the naked eye)  c. Pulvinous: Swelling at the base of the petiole For adjustment of movement towards light may be present or absent  7. Lamina a. type Simple Lobed Compound  Simple leaf With continuous undivided surface Mirror image  Compound leaf The leaf is divided into leaflets Binate Ternate Palmate Pinnate Five or more Several leaflets Two leaflets Three leaflets leaflets arising arranged in pairs from the top of on a rachis. the petiole.  Pinnate Paripinnate Imparipinnate The leaf ends with The leaf ends with a pair of leaflets a single leaflet  b. Incision Lobed Pinnate Palmate One main midrib several veins arising from the top of the petiole Pinnatifid Pinnatipartite Pinnatisect Palmatifid Palmatisect Palmatipartite Pinnatifid Pinnatipartite Pinnatisect Palmatifid Palmatipartite Palmatisect  c. Shape Elliptical Ovate Cordate Lanceolate Sagitate linear Tubular Spathulate Obovate  d. Margin Serrate Crenate Entire Dentate Ciliate e. Apex Acute acuminate obtuse emarginate apiculus truncate mucronate  f. Base Symmetric Asymmetric Decurrent  g. Venation Parallel venation Reticulate venation The veins are parallel to the midrib Pinnate reticulate Palmate reticulate  h. Surface Upper Lower Prominance Colour paler The midrib is more Colour of the midrib or the same or Equally prominant Glabrous or pubescent Glabrous pubescent Lower Upper 8. Texture Papery Leathery Succulent or fleshy 9. Odour odourless Characteristic 10. Taste Bitter Mucilaginous Salty Characteristic