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Questions and Answers
What characteristic is common to all foliage leaves?
What characteristic is common to all foliage leaves?
Which type of leaf is specifically the first leaf born on a branch?
Which type of leaf is specifically the first leaf born on a branch?
What is the purpose of stipules in leaves?
What is the purpose of stipules in leaves?
How are leaves classified when they fall in autumn and bare no expanded leaves during winter?
How are leaves classified when they fall in autumn and bare no expanded leaves during winter?
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What term describes the arrangement of leaves on the stem?
What term describes the arrangement of leaves on the stem?
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Which of the following colors in leaves is associated with the pigment carotene?
Which of the following colors in leaves is associated with the pigment carotene?
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What part of the leaf is referred to as the petiole?
What part of the leaf is referred to as the petiole?
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What type of leaves are described as scale leaves?
What type of leaves are described as scale leaves?
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Which type of leaf texture is described as being very thin?
Which type of leaf texture is described as being very thin?
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In which type of leaf mesophyll is a palisade layer present beneath the upper epidermis only?
In which type of leaf mesophyll is a palisade layer present beneath the upper epidermis only?
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What is the primary function of the epidermis in a leaf?
What is the primary function of the epidermis in a leaf?
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What distinguishes glandular trichomes from non-glandular trichomes?
What distinguishes glandular trichomes from non-glandular trichomes?
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Where is the phloem located within the vascular system of a leaf?
Where is the phloem located within the vascular system of a leaf?
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Which type of non-glandular trichome structure consists of a uniseriate axis branching into numerous unicellular hairs?
Which type of non-glandular trichome structure consists of a uniseriate axis branching into numerous unicellular hairs?
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What type of tissue primarily comprises the cortical tissue found mainly in the midrib?
What type of tissue primarily comprises the cortical tissue found mainly in the midrib?
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Which of the following correctly describes palisade mesophyll?
Which of the following correctly describes palisade mesophyll?
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What type of leaf is characterized by having 2 leaflets only?
What type of leaf is characterized by having 2 leaflets only?
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Which type of leaf has leaflets arranged on a central axis and resembles the midrib of a simple leaf?
Which type of leaf has leaflets arranged on a central axis and resembles the midrib of a simple leaf?
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Which leaf shape is described as heart-shaped?
Which leaf shape is described as heart-shaped?
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What is the primary characteristic of a paripinnate leaf?
What is the primary characteristic of a paripinnate leaf?
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What does the term 'mucronate' refer to in the context of leaf apices?
What does the term 'mucronate' refer to in the context of leaf apices?
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Which of the following describes leaves that have a network pattern of veins?
Which of the following describes leaves that have a network pattern of veins?
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Which margin type has sharp, pointed features directed towards the apex?
Which margin type has sharp, pointed features directed towards the apex?
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A leaf that appears flat and wide with edges parallel near the middle is referred to as?
A leaf that appears flat and wide with edges parallel near the middle is referred to as?
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Study Notes
Leaf Morphology and Anatomy
- A leaf is a lateral outgrowth on a stem.
- It's characterized by a flattened shape, thin texture, chlorophyll presence, and axillary buds/branches.
Types of Leaves
- Prophylls (fore leaves): The first leaf on a branch, simple.
- Foliage leaves: Ordinary, green leaves.
- Scale leaves: Found on subterranean and some aerial stems; thin, membranous, lack chlorophyll.
- Bracts: Leaves with a flower in their axils.
- Floral leaves: Colored sepals, petals, stamens, and carpels.
- Cotyledons (seed leaves): Embryonic leaves.
Foliage Leaves
- Typically green due to chlorophyll.
- In autumn, leaves change color.
- Yellow/orange colors due to xanthophyll and carotene pigments respectively.
- Red colors due to xanthocyanin pigments.
Position of Leaves
- Cauline: Leaves spaced apart on elongated aerial stems.
- Radical: Leaves clustered at the top of a root, at or just above ground level.
Duration of Leaves
- Persistent: Living for a year or more, characteristic of evergreen plants.
- Deciduous: Falling in autumn, causing the plant to be leafless during winter.
Phyllotaxis
- The arrangement of leaves on a stem.
- Alternate or Spiral: Leaves positioned singly at each node.
- Opposite: Leaves in pairs at each node, opposite each other.
- Whorled or Verticillate: Three or more leaves at a node.
Parts of a Complete Leaf
- Lamina (blade): Flattened, leaf surface.
- Petiole (stalk): Connects the leaf to the stem; often slightly enlarged at the base.
- Base: The leaf attachment point, sometimes slightly enlarged.
Stipules
- Lateral outgrowths at the leaf base.
- Protect young axillary buds.
- Assist in photosynthesis.
- Presence of stipules: stipulate leaf.
- Absence of stipules: exstipulate leaf.
Petiole (Leaf Stalk)
- Carries the lamina away from the stem.
- Transports materials to and from the lamina.
- Presence: petiolate leaf.
- Absence: sessile leaf.
Lamina (Leaf Blade) Shape
- Usually green, flattened.
- Simple: Continuous, undivided surface.
- Lobed or divided: Cut into lobes; connected by undivided portion.
- Compound: Segmented into multiple leaflets.
Compound Leaves
- Two or more leaflets.
- Leaflets arranged along a central axis: rachis.
- Binate: Two leaflets.
- Ternate: Three leaflets, one terminal.
- Palmate: Five or more leaflets radiating from the petiole top.
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Pinnate: Several leaflets along a central rachis.
- Paripinnate: Even number of leaflets on either side.
- Imparipinnate: Odd number of leaflets, ending with a single leaflet.
Simple Leaf Characteristics
- Shape: (e.g., linear, ovate, elliptical)
- Apex: Leaf tip (e.g., acute, obtuse, acuminate).
- Margin: Leaf edge (e.g., entire, serrate, dentate).
- Base: Leaf connection point (e.g., rounded, pointed).
- Venation: Arrangement of leaf veins (e.g., parallel, reticulate).
- Texture: Leaf substance (e.g., membranous, papery, coriaceous, succulent).
- Surface: Leaf surface features (e.g., smooth, wrinkled, hairy)
Leaf Shape
- Filiform: Thread-like
- Acicular: Needle-shaped
- Linear: Flat, long, narrow
- Oblong: Flat, wide with parallel edges.
- Lanceolate: Linear, wider at base.
- Ovate: Egg-shaped
- Cordate: Heart-shaped.
- Obcordate: Reversed heart-shaped.
- Obovate: Reversed egg-shaped.
- Spathulate: Spoon-shaped
- Orbicular: Circular
- Elliptical: Wide middle, narrow ends
- Oval: Broadly elliptical
Apex Characteristics
- Acute: Sharp angle.
- Acuminate: Tapering to a point.
- Obtuse: Blunt or rounded.
- Recurved: Curved backwards.
- Mucronate: Terminates in a sharp point.
- Emarginate: Indented at the tip.
- Tendrillate: Thread-like for clinging
Leaf Margin Characteristics
- Entire: Even and smooth.
- Revolute: Rolled back.
- Crenate: Rounded lobes.
- Dentate: Toothed, pointed outward.
- Serrate: Toothed, pointed toward apex.
Leaf Base Characteristics
- Symmetric: Equal both sides of midrib.
- Asymmetric: Unequal both sides of midrib.
- Decurrent: Base continuous downward as wings along petiole.
Venation
- Parallel: Veins run parallel.
- Reticulate: Veins form a network.
Leaf Surface characteristics
- Smooth: Wrinkled.
- Punctate: Dotted projections (oil glands).
- Glabrous: Free of hairs.
- Pubescent or hairy: Covered with short hairs.
Leaf Texture Characteristics
- Membranous: Very thin.
- Papery: Thin like paper.
- Coriaceous: Thick and leathery.
- Succulent: Thick and fleshy.
Microscopic Structure of the Leaf
- Midrib region: Epidermis, cortical tissue, vascular system.
- Lamina region: Epidermis, mesophyll.
Trichomes (hairs)
- Non-glandular (covering): Unicellular, multi-cellular (Uniseriate, biseriate, pluriseriate, stellate, candelabra).
- Glandular: (uniseriate head, biseriate head).
Mesophyll Features
- Palisade: Cylindrical cells perpendicular to the epidermis.
- Spongy tissue: Closely packed chlorenchyma.
- Isolater: Symmetrical mesophyll, palisade on both sides.
- Dorsiventral: Asymmetrical mesophyll, 1 palisade layer.
Stomata
- Arrangement of surrounding epidermal cells, categorized as:
- Paracytic
- Diacytic
- Anisocytic
- Anomocytic
Vascular System (Additional detail)
- Contains xylem (towards upper surface).
- Contains phloem (towards lower surface).
- Medullary rays are visible, radiating lines.
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Description
Explore the fascinating world of leaf morphology and anatomy. This quiz covers various types of leaves, their characteristics, and their positions on plants. Test your understanding of foliage leaves and the factors affecting their color changes.
