This distinctive lichen is common in Denali, found on rocky slopes, tundra and in open woodland. The morphology of white worm varies from long and slender, to squat with many short spurs. White worm lichen is hollow on the inside. This highly abundant species is found across the world, in spite of the fact that is has never been found to produce spores or vegetative propagules. It is completely clonal, and spreads by fragmentation.
Sexual reproduction has never been seen in this species, and before the advent of genetics its relationship to other lichens was a mystery. Small pieces of this lichen are spread by wind, water and gravity. Birds have been known to use Thamnolia vermicularis in their nests, potentially also aiding its dispersal.