southern adder's-tongue

In common with other ferns, Ophioglossum vulgatum is a perennial species of vascular plant. The plant grows from a rhizome base to 10–20 cm (3.9–7.9 in) tall (rarely to 30 cm). It consists of a two-part frond, separated into a 4–12 cm (1.6–4.7 in) rounded diamond-shaped leaf sheath and narrow branchless spore-bearing spike. Leaf fronds are ovate in shape and possess smooth toothless lobes. The spike has around 10–40 segments on each side.

It is native to many regions with a wide scattered distribution: throughout temperate through tropical Africa and throughout the temperate Northern Hemisphere in Europe, northeastern North America, temperate Asia, and Eurasia.

Ophioglossum vulgatum can reproduce vegetatively through new buds that sprout from the rhizome, which allows the plant to form patches. The plant can also reproduce sexually via spores.

Traditional European folk use of leaves and rhizomes as a poultice for wounds. This remedy was sometimes called the "Green Oil of Charity". A tea made from the leaves was used as a traditional European folk remedy for internal bleeding and vomiting.