Occurs on shaded, mossy, limestone rocks. Montreal Mountain, Que. (Provancher.) L'Abord ąPlouffe, rear of the Island of Montreal, Que. (McCord.) Isolated rocks in a shaded pasture, Hemmingford, Que. (Goode.) Limestone rocks west of Hull, and in a ravine near King's Mere, Chelsea, Que. (Fletcher.) Rocky woods, near Oxford Station, on the Ottawa and Prescott Ry., Ont. (Billings.) Crevices of limestone rocks at the railway bridge, Shannonville, and on boulders beyond the "Big Spring" on the Marmora Road, Hastings Co., Ont.; abundant on broken masses of rock at Foster's Fiats, Niagara Falls, Ont.; plentiful at Owen Sound, Ont., on boulders and ledges under the cliffs. (Macoun.) Hamilton and Ancaster, Wentworth Co., and Lake Medad, Halton Co., Ont. (Logic) On shaded, mossy masses of limestone fallen from the cliffs in "The Ravine," Dundas, and at Beamsville, Ont. (Burgess.) Canada (Goldie), to the Saskatchewan (Drummond), in Hook., Fl. Bor. - Am.