Lab 5: Leaf Morphology

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Questions and Answers

Which type of leaf is characterized by having a continuous undivided surface?

Lobed leaf

Simple leaf (correct)

Compound leaf

Binate leaf

What is the defining feature of an imparipinnate leaf?

Contains leaflets arranged in pairs

Has five or more leaflets

Ends with a single leaflet (correct)

Ends with a pair of leaflets

In leaf venation, which type shows veins that are parallel to the midrib?

Palmate reticulate

Parallel venation (correct)

Reticulate venation

Pinnate reticulate

Which term describes a leaf base that is not symmetrical?

Asymmetric Signup and view all the answers

Which of these leaf margins is characterized by small rounded teeth?

Crenate Signup and view all the answers

What type of texture would a leaf described as 'leathery' have?

Thick and tough Signup and view all the answers

Which leaf shape is described as 'lanceolate'?

Long and narrow Signup and view all the answers

Which apex type is characterized by a sharp tip but a long tapering margin?

Acute Signup and view all the answers

Which of the following correctly identifies a characteristic of stipules?

They protect the axillary bud and can be leafy, spiny, or absent. Signup and view all the answers

What distinguishes alternate phyllotaxis from opposite phyllotaxis?

Leaves are located on different nodes with no two leaves sharing the same node. Signup and view all the answers

Which statement accurately describes the characteristics of leaf petioles?

Petiolate leaves have a thick, pulvinous base for phototropic adjustments. Signup and view all the answers

What are the implications of a leaf lamina being described as pubescent?

The leaf lamina has a rough texture due to numerous short hairs. Signup and view all the answers

Which type of leaf base involves a sheath structure?

Exstipulate leaves featuring prominent leaf bases. Signup and view all the answers

How do entire leaves differ from those that are broken?

Entire leaves maintain structural integrity, whereas broken leaves show physical damage. Signup and view all the answers

Which of the following accurately describes leaf venation?

Venation can vary and is essential for supporting leaf structure. Signup and view all the answers

What characterizes whorled or verticillate phyllotaxis?

Three or more leaves emerge from the same node. Signup and view all the answers

Study Notes

Introduction to Pharmacognosy Department

The department is part of the Egyptian Chinese University (ECU).

Lab 5: Introduction of Leaves - Morphology

Leaves are lateral outgrowths from the stem.
Leaves are composed of three main parts: blade, petiole, and base.
The blade (or lamina) is the flat, expanded portion.
The petiole is the stalk that attaches the blade to the stem.
The leaf base is the attachment point to the stem.

Leaf Morphology Scheme

Condition: Fresh or dry; entire or broken pieces are observations to consider.
Color: Observe the color as seen.
Insertion: Cauline (leaves arranged on elongated stem); radical (leaves arranged on a discoid stem crowded on top of the root, e.g., carrot).
Phyllotaxis: Arrangement of leaves on the stem, e.g., alternate, opposite, whorled.
- Alternate: One leaf per node
- Opposite: Two leaves per node, opposite to each other
- Opposite decussate: Opposite leaves with pairs perpendicular to the pairs above or below.
- Whorled or verticillate: Three or more leaves per node.
Leaf base or Phyllopodium:
- Stipules: Lateral projections at the leaf base for protection of axillary buds, may be hairy, leafy, or spiny.
- Sheath: Sheathing leaf base wrapping around the stem.
Leaf Petiole:
- Occurrence: Petiolate (with a petiole) or sessile (without a petiole).
- Characters: Length (short or long).
- Pulvinus (optional): Swelling at the base of the petiole for movement toward light.
Lamina (leaf blade): Classification based on type:
- Simple: Continuous undivided surface.
- Lobed: Pinnate/palmate divisions
- Compound: Divided into leaflets; types of compound leaves include binate, ternate, palmate, and pinnate, and classification within pinnate, includes pari/impari. (Detailed information on further classification as subtypes of compound leaves is presented in a hierarchical / diagram format.)
  - Pinnate: Leaflets arranged along a central axis called a rachis. Classification of pinnately compound leaves includes pari-pinnate (pair of leaflets at the end), and impari-pinnate (a single leaflet at the end).
  - Palmate: Leaflets branching from the same point at the end of the petiole.
Incision: Classification of lobes based on the presence of a midrib in pinnately lobed vs. multiple veins in palmate lobed leaf types.
Pinnatifid, Pinnatipartite, Pinnatisect (classification of pinnately lobed types)
Palmatifid; Palmatipartite; Palmatisect (classification of palmately lobed types)
Shape: Terms like cordate, lanceolate, sagitate, spatulate, obovate, linear, elliptical, ovate.
Margin: Terms like entire, serrate, crenate, dentate, ciliate.
Apex: Terms like acute, acuminate, obtuse, truncate, emarginate, mucronate.
Base: Symmetric, asymmetric, decurrent.
Venation: Parallel (veins parallel to the midrib) and Reticulate; reticulate classification branches into pinnately reticulate/palmately reticulate
Surface: Differences between upper and lower surfaces regarding color, pubescence, and midrib prominence.
Texture: Terms like papery, leathery, succulent/fleshy.
Odour: Odourless or characteristic odors.
Taste: Bitter, mucilaginous, salty, or with characteristic tastes.

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Description

Explore the fascinating world of leaf morphology in this lab quiz. Learn about the three main parts of leaves, their arrangement, and various observations to consider. This quiz will enhance your understanding of leaves as crucial outgrowths of plants.