Day 123: Superficially very similar to Multicolored Rim Lichen (Lecanora pacifica), Ochrolechia laevigata (Smooth Saucer Lichen) has an even closer look-alike in its cousin O. oregonensis (Double-rim Saucer). Two features distinguish them. The first is less obvious: Double-rim has a second narrow whitish-pink band just inside the outer rim, absent in O. laevigata. Much more telling is the fact that Double-rim grows almost exclusively on conifers, and Smooth Saucer will only be found on alder, vine maple and other deciduous species. The disks of Smooth Saucer seldom exceed 3 mm. Those of Double-rim may be up to 1 mm. larger. Both species respond positively to chemical testing with chlorine.
