Structure of a leaf: chlorophyll containing outgrowth of a stem or branch; the site of photosynthesis.
Blade (lamina): main part of the leaf.
Vein: line dividing, but not completely, the leaf into sections.
Midrib: line dividing the leaf in two.
Leafstalk (petiole): part of the leaf that is attached to the stem.
Stem: part of the plant that carries the leaves.
Sheath: part of the leaf that attaches the petiole to the stem.
Stipules: small appendage at the base of the petiole.