A blade of grass, a pine needle, a fern frond, and a maple leaf are all leaves. Most leaves need light, air, and water. Leaves contain green cells to make food for the entire plant.
Leaves look very different however. Every plant has its own distinctive kind of leaf. Leaves help us identify plants like fingerprints identify people.
Needle like leaves can be divided into two groups. Needles can be attached singly to a stem. Other needle like leaves have needles attached in bunches of two, three, or four.
Almost all other leaves can be grouped into broad leaves. Broad leaves can be further classified by their pattern of veins.
In palms, grasses, and other plants, the veins run parallel to one another from the petiole to blade tip.
The branched or webbed group can be classified into two groups--pinnate (featherlike) or palmate (fanlike).
In the pinnate group, the veins branch out from the midrib like barbs of a feather.
The veins in a palmate leaf fan out from the petiole and form a network of smaller veins through the leaf.