adder’s-tongue

noun

1. a fern of the genus Ophioglossum, having one or sometimes two sterile leaves and a fruiting spike.
2. any of several American dogtooth violets.

noun

1. any of several terrestrial ferns of the genus Ophioglossum, esp O. vulgatum, that grow in the N hemisphere and have a spore-bearing body that sticks out like a spike from the leaf: family Ophioglossaceae
2. another name for dogtooth violet