III. D - The Leaf

• Parts

  1. Blade - supports the leaf
  2. Midrib - supports the leaf
  3. Petiole - attaches the blade to the stem
  4. Stripule - nodal outgrowths
• Phyllotaxy - arrangement of leaves among the stem

  1. Alternate
  2. Parallel
  3. Whorled
• Petiolate vs sessile

  1. Petiolate - presence of petiole
  2. Sessile - blade is attached to the node
• Complexity

  1. Simple - single and undivided
  2. Compound
  3. Trifoliate
  4. First pinnate - leaflets attached to rachis
  5. Second pinnate - leaflets attached to rachilla
  6. Palmate - leaflets are attached to central point
• Ventation

  1. Reticulate
  2. Parallel
• General leaf anatomy

  1. Midrib thickness > blade thickness
  2. Midrib
  3. Lamina
  4. Abaxial - lower side; more stomates
  5. Adaxial - upper side; less stomates
• Monocot leaf anatomy

  1. Cuticle - thick
  2. Mesophyll - inner to the blade epidermis
  3. Epidermis
  4. Bulliform cell
  5. Airspace
  6. Stoma
  7. Vascular bundle
  8. Midvein
• Dicot leaf anatomy

  1. Upper epidermis
  2. Palisade mesophyll
  3. Midvein
  4. Vascular bundle
  5. Phloem
  6. Xylem
  7. Collenchyma
  8. Lower epidermis
• Gymnosperm

  1. Epiderimis
  2. Hypodermis
  3. Lobed mesophyll
  4. endodermis
  5. Xylem
  6. Transfussion tissue
  7. Sunken stomate
  8. Resin duct
• Leaf modifications (Type - modification - function)

  1. Bracts - lamina - attracts polinators
  2. Carnivorous - entire leaf - heterotrophic nutrition
  3. Meristematc - margin - asexual reproduction
  4. Phyllods - petiole - additional photosynthetic activity
  5. Spines - entire leaf - defense and prevents water loss
  6. Storage - entire leaf - food storage
  7. Pseudostem - leaf sheath - structural support