Populations of this species remain numerous across its range, however there has been a slight contraction in the extent of northern subpopulations. AOO has declined 36.6%, satisfying the vulnerable criteria A3c

Species of the genus Platismatia were originally placed within Cetraria by Acharius (1803). There are presently 11 species of Platismatia, most of which occur in North America north of Mexico. Molecular phylogenetic analyses support the delimitation of Platismatia tuckermanii as a distinct species in this group (Asher et al. 2023). It was described more than a century and a half ago as Cetraria tuckermanii and has been recognized as a distinct taxon since that time, albeit under a several different synonyms including Cetraria atlantica (Tuck.) Du Rietz, Cetraria lacunosa var. atlantica Tuck. The connection to Cetraria lacunosa led many early records from eastern North America to be placed under that name in natural history collections. It also led many historical western North American specimens of Platismata lacunosa to be placed under the name P. tuckermanii. Despite this nomenclatural confusion, the species are distinct and have well-established allopatric distributions.

Platismatia tuckermanii is widely distributed across temperate eastern North America. It is found most commonly in the Great Lakes-Appalachian region, but ranges from Newfoundland to South Carolina.

Across its range Platismatia tuckermanii is locally abundant where it occurs. There are currently estimated to be more than 55,700 individuals based on the number of extant observations, calculated from a minimum of at least 25 individuals per site). Since 1990 the AOO for this species has declined 36.6% and EOO has declined 18% from the historical values calculated based on the known occurrences post-1924. While its overall range has remained relatively stable, number of occurrences in the northeast United States and Great Lakes region have contracted substantially leading to a concentrated decline in the population within these two regions.

Platismatia tuckermanii grows in temperate forest types across eastern North America, and can be found loosely attached to the bark of trees (Brodo et al. 2001). It is locally abundant where it occurs (Culberson & Culberson 1968). While primarily growing on conifers, it has been found on a variety of hardwood species and even wooden fences (Culberson & Culberson 1968). It is frequently found in tree canopies and on the branches of shrubs in open, high-light habitats (Tripp & Lendemer 2020).

Platismatia tuckermannii faces immediate threats from habitat loss and degradation throughout its range. This includes expansion of housing and urban areas, roads and railroads, agricultural areas, and commercial and industrial areas. While it has been observed persisting in mildly disturbed forests (Culberson & Culberson 1968), it is unlikely to persist in areas subjected to high levels of disturbance. The population has declined substantially in the Northeast and Great Lakes compared to the southern portions of the range, indicating that climate change may be mediating local declines and extirpations in the northern part of its range (Parmesan 2006). While these regional threats are not reflected in the changes in EOO and AOO, these observed demographic changes should be noted.

This species would benefit from long-term monitoring of populations and demographic studies. Niche models using past and present climate data are recommended for identifying drivers of local extinctions in the northern limits of this species’ range.

This species is collected for scientific research. Other human uses have not been documented.

Asher, O. A., Howieson, J., & Lendemer, J. C. (2023). A new perspective on the macrolichen genus Platismatia (Parmeliaceae, Ascomycota) based on molecular and phenotypic data. The Bryologist, 126(1), 1-18.

Culberson, W. L., Culberson, C. F. (1968). The Lichen Genera Cetrelia and Platismatia (Parmeliaceae). Contributions from the United States National Herbarium. Vol. 34. Washington: Smithsonian Institution Press. pp. 449–558 [549].

Parmesan, C. (2006). Ecological and evolutionary responses to recent climate change. Annu. Rev. Ecol. Evol. Syst., 37, 637-669.