Dense clubmoss is a perennial evergreen, non-flowering herb that forms dense mats that rarely exceed 1-in. in height. Stems are compactly branched, leafy and lie along the soil surface. Leaves are simple and awn-tipped, are 1/10 of an inch. long and arranged in dense spirals along the stem.

Its roots are extremely fine, minutely branched and extend 1-2 in. into the soil. Despite their fineness, the extensive branching of dense clubmoss roots makes up as much as 85% of the plant's dry matter.