Lopadium
Crustose lichens containing a trebouxioid alga; thallus areolate, verrucose, squamulose or coralloid-microfruticose; apothecia with a non-algal rim, the rim and disc jet black; rim formed of blocky or rounded cells surrounded by dark red-brown pigment; hymenium of straight, sometimes branched paraphyses with swollen apices, the swollen portion tipped with dark brown pigments in the walls; hypothecium dark brown; asci elliptical or broadly cylindrical, with a thin tholar region that reacts IKI+ dark blue; spores 1 per ascus, muriform with very numerous, blocky cells.
References: Purvis et al. 1992.
| 1a. | Thallus of raised squamules that often branch, sometimes developing into crowded masses of coralloid “isidia”; apothecia uncommon; known from the study area as a terricole, but not an epiphyte …[Lopadium pezizoideum (Ach.) Körber] |
| 1b. | Thallus of areoles that sometimes lift at the edge, but which never develop isidioid structures; almost always fertile; growing on bark and wood, not terrestrial …Lopadium disciforme |
Lopadium disciforme (Flotow) Kullhem
Thallus pale green or olive-brown or chocolate-brown, of large, flat, waxy areoles 0.2-0.4 (‑0.6) mm; apothecia matte jet-black, 0.4-2 mm wide, with a thick, persistent rim that protrudes higher than the disc; spores with at least 100 cells, 70-115 × 20-40 µ.
Reactions: Spot tests all negative.
Contents: No known lichen substances.
Habitat: Over bark of branches and twigs, less often on trunks, above the winter snowpack. All forested elevations.
Similar Species: Lopadium pezizoideum may be only a ground-dwelling form of this species, differing reliably only in the degree to which the areoles ascend from the substrate and how deeply divided they are into narrow segments.
Specimens: Björk 9522; Goward 94-903.
Local Status: Very common.