Two basic forms of leaves can be described considering the way the blade (lamina) is divided. A simple leaf has an undivided blade. However, the leaf may be dissected to form lobes, but the gaps between lobes do not reach to the main vein. A compound leaf has a fully subdivided blade, each leaflet of the blade being separated along a main or secondary vein. The leaflets may have petiolules and stipels, the equivalents of the petioles and stipules of leaves. Because each leaflet can appear to be a simple leaf, it is important to recognize where the petiole occurs to identify a compound leaf. Compound leaves are a characteristic of some families of higher plants, such as the Fabaceae. The middle vein of a compound leaf or a frond, when it is present, is called a rachis.
;Palmately compound: The leaflets all have a common point of attachment at the end of the petiole, radiating like fingers of a hand; for example, Cannabis (hemp) and Aesculus (buckeyes).
;Pinnately compound: Leaflets are arranged either side of the main axis, or rachis.
;Bipinnately compound: Leaves are twice divided: the leaflets (technically "subleaflets") are arranged along a secondary axis that is one of several branching off the rachis. Each leaflet is called a pinnule. The group of pinnules on each secondary vein forms a pinna; for example, Albizia (silk tree).
;Trifoliate (or trifoliolate): A pinnate leaf with just three leaflets; for example, Trifolium (clover), Laburnum (laburnum), and some species of Toxicodendron (for instance, poison ivy).
;Pinnatifid: Pinnately dissected to the central vein, but with the leaflets not entirely separate; for example, Polypodium, some Sorbus (whitebeams). In pinnately veined leaves the central vein is known as the midrib.