Phegopteris connectilis is a species of fern commonly known as the long beech fern, narrow beech fern, or smooth beech fern. Its scientific name comes from the Greek words "phegos" for oak, "pterón" for wing, and "kónnektos" for connected, reflecting its habitat in oak-beech forests and its propensity to produce interconnected fronds. In the Appalachian Mountains, it is often called the "rattlesnake fern" because its rattling fronds are said to warn of the presence of snakes. Other synonyms for Phegopteris connectilis include Thelypteris phegopteris, Polypodium phegopteris, and Dryopteris phegopteris. This fern is a popular choice for woodland gardens and naturalistic plantings.