Adders Tongue is a fern, and is rare, in 2008 a few plants were seen, but in 2009, it was noticed in all the fields of the reserve. It is best seen early in the year before being swamped by the grass, so look for it in March or April.

Being a fern, it doesnt really flower.

Because it is a rare plant in this area, it has been adopted as the logo for the Stewkley Wildlife Reserve.