Occasional on 15- to 70-foot, northeast to north-facing basalt cliffs on steep upper slope of a 160-foot bedrock hill. Shaded beneath Betula cordifolia, B. papyrifera, Picea glauca, Acer spicatum, and Sorbus decora. Scattered clumps and loose patches, mostly in horizontal crevices (some in mats of Dicranum sp. and Polytrichum sp. mosses on narrow ledges).
Associates include Carex deflexa, C. foenea, Cystopteris fragilis, Woodsia ilvensis, Polypodium virginianum, Thelypteris phegopteris, Huperzia selago.