Hypogymnia imshaugii, commonly known as the forked tube lichen, is a common species of foliose lichen in the family Parmeliaceae. It was formally described as a new species by Norwegian botanist Hildur Krog in 1968. It has a grey to gray-green thallus with slender lobes measuring up to 2 mm wide that are branched dichotomously at regular intervals. It has cup- to disc-shaped apothecia that are constricted at the base. The lichen grows on conifer branches, preferring inland habitats that are moderately dry.

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