Very fleshy. Leaves: the sterile portion borne at, or above the middle of the stem, pinnate, with two to eight pairs of lunate lobes, crenate or entire, fertile portion dense; bud for the following year enclosed in the base of the stem.

The Moonworts are extremely curious plants growing from short, erect rootstocks, and clustered fleshy roots. The name refers to the numerous half-moon-shaped lobes which grow near the middle of the stem on the sterile portion of the plant. Once upon a time, the Moonwort was supposed to possess magic properties, and according to Coles, an old writer on botany, would enable the fortunate owner of the plant to "open the locks wherewith dwelling-houses are made fast, if it be put into the keyhole." Drayton called it "Lunary," and thus refers to its wonderworking power: "Then sprinkled she the juice of rue With nine drops of the midnight dew From Lunary distilling."

Botrychium simplex, or Small Moonwort, is also called Little Grape Fern, in allusion to its grape-like clusters of spore cases. It is a graceful, variable plant, and has a single lobe on the stem, the fertile portion being a spike with spore cases in rows on either side of its branches.

Botrychium virginianum, or Rattlesnake Fern, is a much larger, and more robust plant, with a much-divided sterile portion, like a fern leaf, its segments more or less toothed.

Botrychium lanceolatum, or Slender Moonwort, has small fronds, and the sterile segment, which is closely sessile at the top of the long slender stalk, is triangular, ternately twice pinnatifid, with acute lanceolate lobes that are incised or toothed. The veinlets fork from a continuous midvein.