1. Characteristics of Twigs and leaves Along with Leaf Structures
7TH GRADE SCIENCE

2. GENERAL TERMS
leaf — a lateral outgrowth from the stem whose primary function is the manufacturing of food
twig -- a young woody stem to which leaves and buds are attached
branch -- a thicker, older woody stem to which twigs are attached
trunk -- the main vertical stem of a treefruit — the seed-bearing portion of a plant
deciduous — trees on which all leaves fall at the end of every season of growth
evergreen — trees on which leaves remain attached for more than one year

3. twigs

4. Parts of a twig Petiole Node Internodes Lateral/axillary bud
Terminal bud
Terminal bud Scars
Leaf Scar

5. Petiole
A leaf stalk, it attaches the leaf to the stem.

6. the part of a twig between two nodes Node the place on a twig where a
Internode
the part of a twig between two nodes
Node
the place on a
twig where a
leaf is attached
Node
Internode

7. Lateral/axillary Bud
a bud that is situated along the sides of a branch and not at the tip
It may become next years branches or flowers

8. Terminal bud a bud that is at the tip of a stem or branch
Where the branch can grow longer

9. Terminal Bud Scars
Can determine
the age of the
twig by
counting these

10. Leaf/Bud Scar
the scar left on a twig when a leaf falls

12. Leaves

13. Functions of Leaves
Manufacture food for the plant, through process of photosynthesis
Equation for Photosynthesis:
CO2 + H2O  C6H12O6 + O2
Photosynthesis only occurs when light is present

14. Leaf Terms Epidermis: outside layer of the leaf (leaf surface)
Stomata: openings in the leaves where carbon dioxide comes in from the atmosphere (needed for photosynthesis)

16. Leaf Terms
Transpiration: the loss of water vapor from the plant; most water is lost from the stomata, some through the cuticle layer.

17. Parts of a Leaf
Lamina/blade
Leaf Apex
Midrib
Petiole
Stem
Vein

18. Lamina/blade
The blade of the leaf.

19. Leaf Apex
The outer end of a leaf; the end that is opposite the petiole.

20. Midrib
The central rib of a leaf, it is usually continuous with the petiole.

21. Petiole
A leaf stalk, it attaches the leaf to a plant.

22. Stem
The main support of the plant, also called the apex.

23. Vein
One of the many vascular structures on a leaf. Veins provide support for the leaf, and transport both water and food through the leaf.

24. Veins Parallel Palmate Pinnate Up and down From one central location
Off one main vein

25. Types of Leaves
Simple
Compound

26. Simple
Simple Leaves are of one continuous leaf surface, not divided into separate segments.

27. Compound
Compound leaves are composed of many smaller leaflets, each resembling a complete leaf in and of itself.

28. Types of Compound Leaves
Palmate
Odd Pinnate
Even Pinnate

29. Palmate
The leaflets are attached at one plane at the base.

30. Odd Pinnate
Leaflets are on two opposite sides of the axis, with an odd number of leaflets, one at the tip.

31. Even Pinnate
Leaflets are on two opposite sides of the axis, with an even number of leaflets, and paired at the tip.

32. Leaf Arrangement
Alternate
Opposite
Whorled

33. Alternate
Leaves are borne singly at each node.

34. Opposite
Leaves are borne two at each node.

35. Whorled
Three or more leaves are arranged in a circle around the stem.

36. Leaf Shape
Heart
Lance
Oval
Diamond
Round

37. Heart Shaped
The top of the leaf is pointed while the bottom of the leaf is uneven. Making a heart like shape.

38. Lance shaped
Long and narrow

39. Oval shaped
Have a rounded top and bottom.

40. Diamond Shape
The tip is pointed while the base is rounded

41. Round shaped
Completely rounded at the top and bottom

42. Leaf margins Smooth/entire Wavy Serrate (saw toothed) Doubly serrate
lobed

43. Smooth/entire margin
no kind of marginal division or nearly lacking marginal division

44. Wavy margin
having a wavy up and down edge

45. Toothed (serrate) Margin
having sharp, straight-edged teeth pointing to the apex

46. Double serrate margin
primary teeth have smaller secondary teeth

47. Lobed Margins
With Shallow, obtuse or rounded teeth scalloped