Thallus: thin to very thin, +evanescent surface: smooth, white or creamy Apothecia: +elongated (lirelliform), aggregated into groups, sometimes crowded, elongate, branched, often tri-radiate, erumpent to +superficial, 0.11 x (0.1-)0.2-0.4 mm disc: slit-like but expanded with age exciple: thin, black, prominent, strongly inflexed at first hymenium: +hyaline, I-; paraphyses: indistinct, anastomosed; hypothecium: hyaline asci: clavate, with an internal ocular chamber, I-, 40-65 x 12-17 µm, 8-spored ascospores: hyaline initially, becoming pale brown, sole-shaped to obovoid, one cell larger, 12-17 x 4-7 µm Pycnidia: not known Secondary metabolites: not known. Substrate and ecology: on bark of deciduous trees and conifers World distribution: North America, the British Isles (?), and possibly Australasia Sonoran distribution: southern California (McClatchie 1897; Hasse 1906). Notes: Melaspilea constrictella is a very poorly-known species described from Scotland (but according to Hawksworth [1992a] the specimen could be from Australia or New Zealand). The identity of North American material needs clarification and specimens should only very tentatively be given this name.