Chrysothrix Candelaris, Gold Dust Lichen

Day 100: You might mistake Chrysothrix candelaris for a smear of paint when you first notice it on a trailside tree, but in fact it is a lichen commonly called "Gold Dust." It occurs most frequently on bark, but also occasionally on rock. A hand lens will show that it is comprised entirely of tiny sorediate particles, truly resembling the dust from which its common name is derived. A related species (C. chlorina) prefers rock as its substrate, and forms a coarser, thicker crust. Here in the Pacific Northwest, Gold Dust can be found along many shady trails and even on roadside trees, particularly Douglas-fir. Take a closer look when you find it.