Horse parsley is a common name given to the plant "Chamaesium anthemifolium". This plant is also known by other names such as mayweed chamomile, chamomile chamaemelum, and chamomile dog fennel. The plant is native to North America, and it resembles a small bush with feathery leaves. It produces small white flowers that bloom throughout spring and summer. The plant has a strong scent that is similar to chamomile flowers, and it is often used as an herbal remedy to treat digestive problems, headaches, and menstrual cramps. Overall, horse parsley is a versatile plant with several other synonyms that can be used interchangeably.