Parts of the leaf

A typical leaf has three parts: the leaf base (hypopodium), the petiole (mesopodium) and the lamina (epipodium). The leaf base is the part attached to the stem's node, usually protecting the growing bud in its axil; in legumes it often becomes broad and swollen, a modification called the pulvinus (Clitoria, Lablab, Cassia, Erythrina, Butea, Peltophorum), while in many monocot families (Arecaceae, Musaceae, Zingiberaceae, Poaceae) it extends into a tubular sheath that clasps the internode, leaving a scar when the leaf falls. In most dicots the leaf base also bears one or two lateral appendages called stipules - a leaf with stipules is stipulate, one without is exstipulate/estipulate, and stipules mainly protect the leaf while still in the bud; some monocot grasses instead bear an outgrowth called a ligule between the leaf base and lamina, and small stipule-like outgrowths at the base of a compound leaf's leaflets are called stipels. The petiole (leaf stalk) is the cylindrical or flattened stalk that bridges the lamina to the stem - a leaf bearing one is petiolate (Ficus, Hibiscus, Mangifera, Psidium), while a leaf without one is sessile (Calotropis, Gloriosa). The lamina is the expanded, flat, green blade - the main seat of photosynthesis, gas exchan …