Kin to parsley, carrots, dill and cilantro, the type of celery (Apium graveolens var. dulce) most common in the U.S. belongs to the Pascal family, with large, firm stalks that are pale to deeper green and leafy ends. There are several varieties in different hues (shades of gold and red), stalk size and tenderness, and flavor. Celery root, or celeriac (var. rapaceum) and smallage, or Chinese celery (var. secalinum), are closely related to celery. With just 18 calories, one serving (about two medium stalks) of celery packs 40% DV (Daily Value, based on 2,000 calories/day) of bone-protective vitamin K and 10% DV of vitamin A, which supports eye health.