Boreal felt lichen

Erioderma pedicellatum is a foliose cyanolichen with lobes 2–5 cm across, and occasionally reaching 12 cm in diameter. It has a distinctively fuzzy upper surface that is greyish-brown when dry, and slate-blue when moist. Its underside is white, and its edges usually curl upwards, giving it the appearance of having a white fringe. It differs from the two other North American species of Erioderma by lacking soredia, and by having small, reddish-brown apothecia on its upper surface.

Erioderma pedicellatum is distributed in the Northern Hemisphere. It can be found on both sides of the Atlantic and Pacific coastal regions.

Atlantic populations. Erioderma pedicellatum was once prevalent in Norway, Sweden, and the provinces of New Brunswick, Nova Scotia, and Newfoundland in Atlantic Canada. In Europe, it was first discovered in three nearby sites in the boreal rainforests of Norway (1938–39) and in five forested canyons in Värmland, Sweden (1941), but logging soon led to its extinction from all known European sites. However, during later intensive searches for this lichen, a few individuals were found in two new sites and one old site, and a few thousand individuals were found in one site in Rendalen, eastern Norway. In Canada, it is no longer found in New Brunswick, and as of 2009 there were fewer than 200 individuals known in Nova Scotia. In Newfoundland, it is estimated that there are between 15,000 and 20,000 individuals. The remaining habitat in Newfoundland is therefore critical for the global survival of this species. Lockyer's Waters and Hall's Gullies on the Avalon Peninsula to the southeast, and Bay d'Espoir to the south, are three of the Newfoundland's most prolific rare lichen habitats, and are important for the conservation of E. pedicellatum. The lichen was recorded as new to Quebec in 2022.

Pacific populations. …

Erioderma pedicellatum grows on mossy trunks and branches of trees on slopes in areas that have a constant supply of moisture, and are rich in Sphagnum moss. It is usually found on balsam fir, occasionally on black spruce, and rarely on white spruce, red maple, or white birch. It does not appear to grow directly on bare bark, and is usually found growing in association with the epiphytic liverwort Frullania asagrayana. Old growth balsam fir boreal forests in wet areas of eastern Canada regenerate by gap replacement, which creates many forest stands of different ages, while still maintaining a full or partial canopy. It appears that this diversity in forest stands age is necessary for a viable population of E. pedicellatum. Natural dispersal of E. pedicellatum is evidently possible within these old-growth forests, but there are no known examples of E. pedicellatum establishing in stands previously clear-cut. A healthy, mature specimen of E. pedicellatum can grow at a rate of 11 to 14 mm per year, and populations of this lichen have a generation time of about 30 years. The species sexually reproduces. However, as with most lichen, considerable information in understanding E. …