Slender moonwort (Botrychium lineare) is a member of the adder’s-tongue family, and is described as a small perennial fern, emerging from the ground as a single stalk, which divides into two above ground portions. The above-ground structures include a 2-to-7 inch long sterile pale green leaf and an equal to slightly taller fertile stalk of similar color, containing grape cluster-like structures. It is considered to be one of the more distinctive moonworts. A specific habitat description for slender moonwort is problematic because of its current and historically disjunct distribution in North America. The plant has been described from habitats ranging from sea level in Alaska to over 9,840 ft at sites in Boulder County, Colorado. Habitats in which the plant occurs include closed forest understories, open grasslands and disturbed roadsides. States in which Botrychium lineare is known to occur: Currently found in Alaska, Colorado, Minnesota, Montana, Oregon, South Dakota, Washington, and Wyoming; and Alberta and Yukon Territory, Canada. Historically, it has been also found in California; Idaho, and Utah; Quebec and New Brunswick, Canada. Countries in which Botrychium lineare is known to occur: United States, Canada.