Pom-pom Shadow Lichen

Pom-pom Shadow Lichen is a common wreath lichen. It occurs in Europe, North America, Central America, and South America. It occurs in the United States and southern Canada east of the Great Plains, and there are just a handful of records in the west. It is common in Minnesota.

Pom-pom Shadow Lichen is found in well-lit forests on nutrient-rich substrates. It is most common in secondary succession forests, but it is also found in climax forests. It grows on the bark of all kinds of trees. It rarely grows on rock.

The vegetative body (thallus) is leaf-like (foliose). It is divided into radiating lobes forming a circular or irregular rosette that is usually up to ¾″ to 1 3⁄16″ (2 to 3 cm) in diameter. It is held to the substrate (bark) by black, unbranched, root-like structures (rhizines). The rhizines are often conspicuous from above, extending beyond the edges of the thalli. The primary lobes are usually long and narrow, they have straight sides, and they are non-overlapping. Occasionally some are irregularly rounded and are partially overlapping. They are flat and usually 3 ⁄256″ to 1⁄32″ (0.3 to 1.0 mm) wide, but sometimes up to 1 ⁄16″ (3 mm) wide. The upper surface is gray to grayish brown. The underside of the thallus is black, sometimes paler at the lobe ends. The upper and lower surfaces of the lichen are formed of tightly-packed, interwoven, fungal threads (hyphae) going in all directions (paraplectenchymatous). Hyphae are the tiny, thread-like structures that make up the body of the fungus. The paraplectenchymatous lower surface is one of the features that distinguish the genus Phaeophyscia from the genus Physcia. Cap-like, cortex-free areas of the thallus (soralia), at the ends of the lobes, produce powdery to granular reproductive growths (soredia). The underside of the thallus is black, sometimes paler at the lobe ends.

Disk-like, spore-producing structures (apothecia) are uncommon to rare. When present, they are up to ⅛″ (3 mm) in diameter. The margin usually has a corona of black rhizines.

Trees

Foliose

Well-lit forests

Sources

4, 24, 26, 29, 30, 77, 81.

Common

This species was originally described as Physcia pusilloides in 1931. In a later review of the lichen genus Physcia (Moberg, 1977) the author erected the new genus Phaeophyscia for the 8 Finnish species species that were formerly in the Physcia orbicularis group, which lack atranorin, often have a brownish coloration, and possess ellipsoid conidia less than 4 µm in length. In 1978 Physcia pusilloides was moved to the genus Phaeophyscia.

Phaeophyscia pusilloides
amadej2008

Location: Lake Shore, MN

Bristle beard lichen (hanging), also pom pom shadow lichen, powder tipped-shadow lichen?