What is cilantro explains the relationship between coriander and cilantro while also explaining when to use which and what to substitute if you don't have any.
Cilantro is an annual herb grown for its culinary and medicinal properties.
The three images above are all pictures of cilantro plants. There are several varieties or types available to gardeners. Most sport wide, flat leaves that look a lot like those of Italian parsley. In fact, you could easily confuse the flat-leaved types for parsley when shopping for cilantro in the grocery store. Other types have more finely cut leaves like those of Confetti.
When a recipe calls for cilantro, it is referring to the leaves of the Coriandrum sativum or coriander plant.
When a recipe calls for coriander, it is referring to the small, brown seeds of the Coriandrum sativum plant. Each plant will produce about a quarter cup of the aromatic 1/8" seeds during its life.
These seeds can be saved and planted the following spring to produce a crop of their own, or used whole or ground in recipes.
Same plant, different parts. The leaves (cilantro) are chopped and added to Mexican, Chinese, and Middle Eastern dishes where their pungent flavor is desired.
The lemony seeds (coriander) are used as a baking spice and in Indian curry.
Most recipes will be quite specific about which one is required.
Knowing cilantro's flavor profile might help you to mix up a closer approximation of it in a pinch.
Fresh cilantro tastes like a combination of parsley, lovage, and juniper berries. There is a tangy bitterness in it which has been likened to citrus peel, sage, or rosemary.
Coriander tastes like a a mixture of cardamom and cloves with a pinch of white pepper thrown in.