Finger lichen is a distinctive fruticose species, found growing upright in the tundra and in open conifer woodlands. Individuals are typically unbranched, but sometimes produce short spur branches. Finger lichen is always hollow, typically upright, 2-7 cm tall, and relativly wide, 0.5-1.5 cm across. The thallus is pale or dark yellow, often with a brownish base in sun-exposed situations. Finger lichens only rarely produce apothecia, which look like brown eyes. There are no other species in Denali that could be confused with Dactylina arctica. The other member of the genus present in the area, Dactylina ramulosa, is shorter, purplish and much branched.
Finger lichen only infrequently reproduces sexually. Typically, it spreads clonally through fragmentation.