Description: Thalli grow as clusters of light green, cylindrical to flattened hollow tubes, often wrinkled or twisted, arising from a discoidal cushion.  This species usually does not exceed 5-10 cm (2-4 in) tall so is usually shorter than U. intestinalis,< 5-7 μm diam) than those of that species. Habitat: This species is found growing on cobble, boulders, bedrock, barnacles, driftwood and even other algae throughout the intertidal in semi-protected and protected habitats, especially if recently disturbed. Similar taxa:: Pseudothrix borealis, Ulva intestinalis.