Leaf - Introduction,Structure of A Leaf Structure of Leaves Though leaves of different plants are different, they have some common features like midrib, margin, veins, leaf apex, leaf stalk.The Petiole is a short length of stem that joins the leaf to stem.

1. The Leaf of The Plant
Mrs.Mehwish

2. THE OBJECTIVE ARE
1.Defination of leaf
2.Morphology Of leaf
3.Types Of leaf
4.Function Of leaf
5.Venation Of leaf
6.Important Terms of leaf

3. DEFINITION OF
LEAF
Leaf is an organ of vascular plants and
the food making factories of green
plants. These are the chief
photosynthetic organs of plants.

4. MORPHOLOGY OF
LEAF
External structure of leaf is called Morphology. Leaf consists of three main
parts which are following :
Lamina(green flattened portion of leaf)
Petiole(raises the lamina to expose it to the sunlight)
Leaf Base(the part of leaf that attached to the stem)

5. TYPES OF
LEAVES
Simple Leaf Compound Leaf
Pinnate Compound Palmate Compound
Leaf Leaf
Peripinnate Imperipinnate Bifoliate Multifoliate
Unifoliate Trifoliate

6. EXPLANATION :
SIMPLE LEAF :
A leaf whose blade is not divided to the midrib even though lobed is called
simple leaf. (e.g., peepal)
COMPOUND LEAF :
A leaf in which the blade is divided to the midrib forming two or more
distinct blades or leaflets on the common axis is called a compound leaf.
TYPES OF COMPOUND LEAF :
Compound Leaf has two types:
1. Pinnate Compound Leaf
2. Palmate Compound Leaf
1. PINNATE COMPOUND LEAF :
A leaf resembling a feather having the leaflets on each side of the common
axis is called pinnate compound leaf . ( e.g., Rose)

7. TYPES OF PINNATE COMPOUND LEAF :
A pinnate compound leaf is of two types:
Paripinnate Compound Leaf
Imparipinnate Compound Leaf
PARIPINNATE COMPOUND LEAF :
If the number of leaflets is even in the leaf is called
paripinnate compound leaf .(e.g., Cassia Fistula)
IMPERIPINNATE COMPOUND LEAF :
If the number of leaflets are odd in the leaf is called
imperipinnate compound leaf .(e.g., Rosa Indica)
2. PALMATE COMPOUND LEAF :
A leaf with leaflets that originate from a common point at the
end of the petiole is called palmate compound leaf .(e.g., Date-Palm)
TYPES OF PALMATE COMPOUND LEAF :
There are four types of palmate compound leaf :

8. Unifoliate(if palmate compound leaf contains a single leaflet) e.g., Citrus
Bifoliate(if palmate compound leaf contain two leaflets) e.g., Gulmohar Leaf
Trifoliate(if palmate compound leaf contain three leaflets) e.g., Oxalis
Multifoliate(if palmate compound leaf have more than three leaflets) e.g., Cotton Tree

9. VENATION OF LEAVES
DEFINATION:
The arrangement of veins and veinlets(vascular bundles) in the leaf lamina is
called Venation.
TYPES OF VENATION: Unicostate
There are two types of venation:
Parallel Venation Multicostate
Reticulate Venation Unicostate
Multicostate

10. PARALLEL VENATION :
Parallel Venation is the term used to describe the arrangement
of monocotyledonous plants.The veins in the leaf are arranged
parallel to each other.
TYPES OF PARALLEL VENATION :
Parallel Venation is of two types:
Unicostate(if there is a single midrib in the leaf lamina)
Multicostate(if more than one midribs are present in the leaf lamina)
EXAMPLE :
Grasses,Cereals,Onion & Banana.
RETICULATE VENATION :
When the veins of leaf show numerous irregular inter connections giving the
appearance of network it is called reticulate venation.It is characteristics of dicots.

11. TYPES OF RETICULATE VENATION :
There are two types of reticulate venation:
Unicostate(when a single midrib is present in the leaf
lamina) e.g., Mango,Peepal etc.
Multicostate(When more than one midrib is present in the
leaf lamina) e.g., Castor Oil Plant.

12. KINDS OF LEAVES
There are following taxonomic terms or kinds are used to describe the leaf and its parts :
Foliage Leaves (ordinary green leaves which carry on photosynthesis)
Cotyledonary Leaves (found in seeds and serve as food storage )
Scale Leaves (small undeveloped leaves which are sessile & green.
Function as protection.Store food and become thick & fleshy.)
Bract & Bracteoles (leaves of flowering shoots are known as bracts.
they are scale like or green and bear flower in their axial.)
Floral Leaves (specialized leaves which form the parts of flower , are
known as sepal,petals,stamens & carpels.)

13. FUNCTIONS OF
LEAF: There are following functions of leaf in
plants:
1. Manufacture of
Food
2. Interchange of
Gases
3. Evaporation of
Water
4. Storage of Food
5. Vegetative
Propagation