Tofieldia pusilla is a small herb in the lily family (Liliaceae) that grows in moist to wet areas from bogs in boreal areas to alpine seeps and meadows. This relatively common species has a slender, leafless greenish stem and a dense terminal cluster of white flowers. Plants grow 2-20 cm from a short rhizome, found in boggy places. The leaves are basal, 3-nerved, stiff and sword-shaped, arranged like a fan through which the stem rises. There are no stem leaves or bracts at the top of the stem (as in this species close relative Tofieldia coccinea). Stems are topped by usually one, sometimes two, clusters of small flowers, which at first are tightly-packed, and later become less aggregated. The small flowers are usually greenish white or yellowish in color (never red or purple). Flowers have six tepals, six stamens and a 3-styled pistil. The fruit is a dry, spherical capsule, containing 15 to 30 seeds. It is less stout (with narrower leaves) than its close relative Tofieldia coccinea, and lacks a stem leaf.

Tofieldia pusilla flowers in June and July, depending on the site conditions.

T. pusilla is monoecious with bisexual flowers. Flowers are possibly insect-pollinated, but this species' reproductive biology has not been studied. Seeds are dispersed by gravity and wind.

This species is considered a calciphile, although it occurs in acidic, boggy places in Denali with some frequency.

Moist to wet sites.