Festuca lenensis is a small, densely tufted perennial grass endemic to former Beringia that grows in dry, south-exposed terrain (tundra and rubble) in the northeastern quadrant of Denali north of the Alaska Range crest, in the subalpine to alpine zones. This species has bluish-gray leaves (finely pubescent) and a spike-like panicle. Plants grow 10-30 cm tall from fibrous roots. Leaves are basal, shorter than stems, thread-like (< 1 mm wide), folded, and scabrous. Stems are slightly scabrous. The inflorescence is a relatively narrow panicle, 1-3 cm long. Spikelets are 3-5 flowered, green with purple tinges. Flowers are bisexual. Glumes are lanceolate and glabrous. Lemmas have an awn (up to 3 mm long) that arises from the tip. Anthers are relatively large, ~2-4 mm long. The fruit is single-seeded, indehiscent and dry. Key characters for identifying this species include its tufted habit, short height and long anthers.
Festuca lenensis typically flowers mid to late summer, depending on micro-site conditions.
F. lenensis is monoecious, with stamens and pistils in the same florets (bisexual). Flowers are wind pollinated. Seeds are most likely wind dispersed.
F. lenensis has an arctic-alpine, amphi-Beringian distribution ranging from Siberia to Alaska, Yukon, and Northwest Territory. In Alaska, F. lenensis occurs in the Alaska Range, Interior mountains, Brooks Range and isolated sites on the Arctic slope. In Denali, F. lenensis is rare, occurring in isolated localities in the mountains of the northeastern quadrant of the park north of the Alaska Range crest.
This species is observed in the park at elevations from 459 m to 1275 m, with an average site elevation of 920 m. It prefers steeply inclined slopes with an average angle of 20 degrees. It is more commonly seen on south-facing aspects.