Celery seed by John Spottiswood.

Celery seed is used to impart a celery flavor to stews, pickles, and other dishes. Use it sparingly--a little goes a long way. Ground celery seed is sometimes called celery powder. Substitutes: celery (One teaspoon = 2 tablespoons minced celery tops) OR dill seed OR celery salt (reduce the salt elsewhere in the recipe)