Synopsis: Large, appressed or trailing, puffy, often nodulose lobes with sparse to abundant perforations in lobe tips and axils; lobe cavity with dark ceilings and floors; medullary spot tests negative.
Distribution: Alaska to California, inland to Montana; North American endemic. Although broadly sympatric, H. apinnata appears to be somewhat more widespread than H. enteromorpha. In particular, H. apinnata seems to extend farther north and west along the Pacific coast of Alaska (to Attu Island), and is usually the more common of the two species in inland localities. Here it is especially common in the glacial refugia of the Clearwater Drainage in Idaho, where it occurs in oldgrowth forests at low to middle elevations.
Substrate Notes: Most often on conifers, occasionally on hardwood trees and shrubs Abundance in North America: Common Substrate: Typically Host: Conifers and hardwoods, both bark and wood On Rock: Never On Moss/Detritus/Sod: Never Authority: Goward & McCune References: Goward & McCune (1993) Synonymy: None
Habit Appressed: Sometimes Habit Pendulous: Sometimes Habit Erect to Suberect: Rarely Size (cm): Mean: 15 SD: 7.5 Upper Color- White to Greenish Gray: White to greenish gray Upper Surface Brown when Solarized: Blackish or unknown Dark Mottles: Often present Black Border: Often present Lobes Separated: Contiguous or separate Lobe Outline: Nodulose Upper Surface Texture: Smooth to weakly rugose Branching: Isotomic dichot. Budding: Absent or rare Lobe Width (mm): Mean: 3.5 SD: 1 Lobe Tips, Axils, and/or Lower Surface Perforated: Almost always Lobe Tips Perforated: Perforate Lower Surface Perforated: Perforate Cavernulae: Never Thallus Texture: Cartilaginous Medulla: Almost always Ceiling Color: Dark Floor Color: Dark