III. C - The Stem

• Stem morphology

  1. Node - point where the leaf is attached to
  2. Internode - between nodes
  3. Petiole - small section between leaf and stem
  4. Leaf sheath - surrounds the internode
  5. Leaf scar - traces of leaf
  6. Bundle scar - dots; vascular bundles
  7. Terminal bud - bud primordia
  8. Axillary bud - between leaf and stem
  9. Lenticel - protrusions
• Stem modifications (type - modification - function)

  1. Bulb - vertically growing; reduced - gives rise to adventitious roots
  2. Cladode - flat; leaf-like - photosynthesis or water storage
  3. Corm - shorter/underground; food storage
  4. Rhizome - fleshy; roots and shoots from the node; asexual reproducton/storage
  5. Stolon - plantlets grow around node - asexual reproduction
  6. Tendril - coil-like - anchorage
  7. Thorn - THORN BRUH; axillary bud are thorns - protection
  8. Tuber - enlarged - stores food
• Monocot stem anatomy (tissue - contains/function)

  1. Epidermis - fibers
  2. Vascular bundle
  3. Bundle sheath - surrounds vascular bundle
  4. Phloem - sieve tube element + companion cell
  5. Xylem - protoxylem inner (endarch)
  6. Ground tissue
  7. Lacuna
• Young dicot stem anatomy

  1. Epidermis
  2. Ground tissue
  3. Phloem
  4. Metaxylem
  5. Protoxylem
  6. Pith
• Old dicot stem anatomy (part - function)

  1. Lenticel - gas exchange
  2. Phellem
  3. Phellogen
  4. Phelloderm
  5. Sclerenchyma
  6. Cortex
  7. Secondary phloem - exarch growth; compresses cortex
  8. Vascular cambium - between xylem and phloem
  9. Xylem ray
  10. Secondary xylem - endarch growth
  11. Xylem ray - transport water
• Gymnosperm stem anatomy

  1. Periderm - cork; cork cambium; cork parenhcyma
  2. Secondary phloem
  3. Vascular cambium
  4. Tracheids
  5. Resin duct