Asplenium scolopendrium or hart's tongue fern is an evergeen limestone-loving plant. Two varieties of the genus exist. They are nearly impossible to distinguish by form—the clearest distinction is that the American variety is tetraploid and var. scolopendium is diploid. Variety scolopendrium is found primarily in Europe, but is also found in parts of Asia and northern Africa. Variety americana is rare and found in isolated populations in North America. Some botanists place one of these populations, found in Mexico, into a third variety—lindenii. Our plants and virtually any found in cultivation are of var. scolopendrium—var. americanum performs poorly in cultivation—it barely survives in the wild. Plants are quite variable and the species hybridizes with other Aspleniums. Several forms have been selected for ornamental use.

Asplenium scolopendrium spreads by rhizomes to form drifts in shady areas, growing slowly, but needing little attention from the gardener. The erect leaves are 10-60 cm long and 3-6 cm wide—in extreme cases they may grow to 90 cm by 10 cm. The two rows of lines of sori arranged along the rachis of the leaf were thought to resemble a centipede. The species takes its name from this appearance—scolopendra is Greek for centipede.