1. (External & Internal Structures)
PLANTS
(External & Internal Structures)
(Part 2)

2. Shoot system Root system leaf blade axillary bud petiole node
vascular tissue
shoot apical meristem
terminal bud
internode
Shoot
system
vascular tissue
root tip
vascular tissue
root hair
root cap
root apical meristem
Root
system
dermal tissue
ground tissue
vascular tissue

3. The Stem

4. Morphology of a
Dicot Stem

5. shoot apical meristem
leaf scar
node
bundle scar
internode
lenticel

6. Magnified section of the shoot apical meristem
Leaf primordium
Young leaf
Axillary bud

7. Meristematic region Enlargement region Protoderm Ground meristem
epidermis
cortex
Ground meristem
pith
phloem
Procambium
vascular cambium
xylem

8. Morphology of a
Monocot Stem

9. Intercalary Meristem
Occur only in monocot (particularly grass) stems at the base of nodes and leaf blades.
Capable of cell division and allow for rapid growth and regrowth of many monocots.
Leaf regrowth in grasses evolved in response to damage by grazing herbivores.

10. Cross section of a monocot stem

11. vascular bundle bundle sheath companion cell phloem sieve tube
pitted vessel
xylem
annular vessel
air space

12. Cross section of a dicot stem (herbaceous)

13. vascular bundle phloem fiber phloem parenchyma sieve tube
companion cell
vascular cambium
tracheid
vessel
xylem parenchyma
xylem fiber

14. Vascular bundle of a dicot stem
phloem
vascular cambium
interfascicular cambium
fascicular cambium
xylem

15. Secondary Growth of Dicot Stems

16. Woody dicot stem Periderm Primary phloem Secondary phloem
Secondary xylem
Primary xylem
pith

17. lenticels
phellem
phellogen
phelloderm

19. Woody Dicot Stem

20. Bark
Sapwood
Annual rings
Heartwood

21. Modified Roots

22. For Support Twines Tendrils Morning Glory (Ipomea sp.)
Squash (Cucurbita sp.)
Twines
Tendrils

23. Clinging roots at the nodes
For Support
Bougainvillea (Bougainvillea sp.)
Hydrangea (Hydrangea petiolaris)
Scramblers (Hooks)
Clinging roots at the nodes

24. Phylloclades – green, flattened, thin, leaf-like structures
For Photosynthesis
Stick plant (Euphorbia tirucalli)
Mimosa (Acacia cyanophylla)
Green stem
Phylloclades – green, flattened, thin, leaf-like structures

25. Enlarged, thickened of fleshy subterranean stem
For Storage
For Protection
Onion (Allium cepa)
Rose (Rosa sp.)
Enlarged, thickened of fleshy subterranean stem
Thorns

26. For Reproduction stolons runners Bermuda grass (Cynodon dactylon)
Strawberry (Fragania sp.)
stolons
runners