Leaves come in different shapes and arrangements but all perform the basic function of producing food for plants. There are four basic leaf shapes - broad and flat, long and narrow, needlelike, and scaly. Leaves can be arranged opposite, alternate, whorled, or in a basal rosette. Leaf margins can be entire, toothed, wavy or lobed. Leaves are either simple, with one blade, or compound, with multiple blades joined to a petiole. Compound leaves can be palmately or pinnately arranged.

1. Chapter 2 Lesson 6 Pgs. 62-64 For Student Use Only

2. Observing Leaves Leaves are al different, but they are also alike. All leaves produce food for plants. All leaves have some basic shape.

3. Observing Leaves All leaves have 4 basic shapes: Broad, Flat Leaves Long, Narrow Leaves Needlelike Leaves Scaly Leaves

4. Observing Leaves Leaf Arrangements: Opposite- grow in pairs from a point in a stem and opposite sides Alternate- individual leaves that grow in an alternating pattern along the stem

5. Observing Leaves Leaf Arrangements: Whorled- three or more leaves growing from the same point or node on the stem Rosette (or basal)- a cluster of leaves growing around the base of the plant All leaves fit one of these common arrangements.

6. Observing Leaves Leaf Margins (or edges): You can identify plants also by edge of leaf Entire- smooth and unbroken lines Toothed- jagged with small or large “teeth” Wavy- curved bumps that look like ripples Lobed- has lobes that come from one center

7. Observing Leaves Simple or Compound Leaves: Parts of Leaves: Petiole- a stalk that the blade of the leaf is attached Blade- the broad, flat portion of a leaf Simple Leaves One blade attached to the petiole Compound Leaves More than one blade joined to a petiole

8. Observing Leaves Simple or Compound Leaves: Parts or Names of leaves: Leaflets: multiple blades of a compound leaf Sessile- have not petioles and attach directly to the stem

9. Observing Leaves Simple or Compound Leaves: Leaf Venation Parellel Venation- the main veins run seemingly parellel to each other Monocots- parellel veins Dicots- branching veins Pinnate Venation- veins branching from one main vein Plamate venation- small veins branching from more than one main vein

10. Observing Leaves Simple or Compound Leaves: Leaf Venation Palmately Compund- all leaflets attach to a common point at the tip of the petiole Pinnately Compound- leaflets are located at intervals along the petiole