Coriandrum sativum is an annual herb in the carrot family, Apiaceae. The fresh leaves and stems are called cilantro, while the dried seeds are referred to as coriander. This fast-growing, short-lived herb changes significantly throughout its life cycle, adapting from a low, leafy bundle to a tall, flowering stalk.
Identifying Features of the Leaves and Stems
The cilantro plant begins as a low rosette of leaves close to the ground, which are prized for culinary use. The basal leaves are broad, fan-shaped, and often have three lobes with scalloped or slightly serrated edges. As the plant matures, the leaves higher up the stem change, becoming smaller and finely divided. This upper foliage takes on a delicate, lacy, and fern-like appearance.
The plant reaches a height of 1 to 2 feet during this initial growth phase. Its stems are thin, flexible, and tender, allowing them to be easily chopped and consumed with the leaves. The stems contain concentrated flavor compounds and are often used as a base for sauces and curries. The characteristic scent of the leaves is a strong, polarizing aroma, often described as bright, citrusy, or soapy, caused by aldehyde compounds.
The Transition to Flowering and Seed
Cilantro is a cool-season plant. A significant shift in its appearance occurs when it “bolts,” a process triggered by rising temperatures or longer daylight hours. Bolting is the plant’s natural response to stress, shifting energy from producing edible leaves to forming a flower stalk and seeds. A rigid, elongated stem shoots up rapidly, sometimes reaching 2 to 3 feet in height.
The leaves on this tall, flowering stem are the finely divided, lacy structures, unlike the basal leaves. At this stage, the flavor of the leaves is diminished and often takes on a tougher, more bitter taste. Small clusters of flowers, known as umbels, form at the top of the stalk, appearing white or pale pink. These flowers eventually mature into the round, tan-colored fruits that are harvested and dried to become the spice coriander.
Comparing Cilantro to Look-Alike Herbs
Cilantro is frequently confused with flat-leaf parsley (Italian parsley), as both are green, leafy herbs from the same plant family, Apiaceae. Cilantro leaves tend to be more rounded in outline, with edges that are scalloped and deeply lobed, giving them a more delicate appearance.
In contrast, flat-leaf parsley has leaflets that are more pointed and flatter, with sharply jagged or serrated edges. The most definitive way to identify cilantro is by its powerful, distinct aroma. Crushing a leaf releases a strong, pungent scent that is immediately recognizable and contrasts sharply with the milder, fresh, and grassy fragrance of parsley.