Hypogymnia physodes (Hooded Tube) is a lovely hollow lichen, named in part for its naked lower surface. Where other leaf-like lichens produce root-like structures below, Hooded tube is smooth and black.. Like Hooded Rosette, Hooded Tube gets around by producing powdery propagules in inflated hoods at the tips of its lobes, but you’ll have to crane your neck to see inside. . It’s worth it – Hooded tube is a lovely part of Edmonton’s river valley flora, found on rotted wood and trees throughout the city.