Punctelia missouriensis is a foliose lichen that is common and widespread in eastern North America with scattered disjunct occurrences in Mexico. It is under threat from conversion of natural habitat to agriculture, suppression of natural regimes, and other changes human caused shifts or alternations in oak savanna habitats. Despite these threats, and an inferred decline in EOO of 9% during the last three generations, new occurrences continue to be documented and the species is not known to be under significant threat of extinction at this time. For these reasons it is assessed as Least Concern.

Fieldwork in the early 1990’s revealed the presence of this species in the midwestern United states where lichen inventories were historically sparse (Wilhelm & Douglas, 1992). Despite being morphologically distinctive, misidentification of P. missouriensis has been common within herbaria and published literature. Local rarity at sites outside of the Midwest, combined with propagules that can be easily misinterpreted morphologically, has caused confusion with the more common sorediate species P. caseana and P. jeckeri.

Punctelia missouriensis has a northern temperate eastern North American distribution that is very similar to other common foliose species like Parmotrema perforatum and P. hypotropum. Its range extends southward into Northern and Central Mexico, where it is infrequent but widespread at disjunct montane locations (Egan & Lendemer, 2016).

The population is suspected to be stable based on the fact it is abundant and common within the center of its range in the Midwestern United States, and extant but less frequent in the Appalachian Mountains of the eastern United States. While the extant area of occurrence (AOO) is inferred to have declined by 9% over the last three generations, new occurrences continue to be found across its range. There has not been a systematic effort to relocate the species at all known historical sites across its range and assessment of population size and trends, requires reexamination of those historic sites. Although the population is inferred to have declined based on occurrence data, the discovery of new sites suggests that further study is needed to determine whether it is stable or decreasing.

The species is found commonly within open mixed hardwood forests and oak savannas in the Midwestern United States.  Further east, it is most found within early successional temperate forests and open glade habitats where these clearings are ecologically like the center of it range (Wilhelm & Douglas, 1992). This species is frequently found on the bark and branches of hardwood trees, especially oaks, maples, and elms (Lendemer et al. 2013). Collections have been made on coniferous trees like pines and juniper, especially in Mexico (Egan & Lendemer, 2016). It is not uncommon to find colonies growing on rocks associated with these plant communities, notably in the Appalachian Mountains (Lendemer & Noell, 2018).

Human mediated burning regimes in eastern North America resulted in a mosaic of oak savannas and wooded landscapes that were the dominant vegetation types for large areas of the extant population (Dey et al. 2014). In the past century, these ecosystems have become fragmented and reduced in extent due to conversion to agriculture and succession following suppression fire (Vander Yacht et al. 2017). These large-scale changes across its range have reduced the frequency and abundance of suitable trees to host this species.

High lichen species richness in the southern Appalachians has been shown to be linked to local habitat quality (Boggess et al. 2024, Tripp et al. 2019). Decades of research show that most species are intolerant of degradation of suitable habitat and are slow to establish (Will-Wolf et al. 2017). The eastern north oak savanna ecosystem has been severely fragmented and is now mostly restricted to areas with some degree of easement or conservation effort (Dey et al. 2014). The occurrence of Punctelia missouriensis in these remaining fragments of natural habitat could be invaluable for its management and conservation. Occurrences outside of protected areas could guide future land protections and suggest areas for reintroduction of historical burning regimes necessary for restoration of suitable habitats. Taxonomic training of species-specific characters would aid researchers and land managers in identification and separation from similar looking co-occurring taxa. Furthermore, training of the public would bring increased awareness and appreciation that can lead to further documentation of the species and collection of demographic data.

New occurrences continue to be found throughout the population at sites that are suitable for the species. Reexamination of the occurrences at historical sites is necessary to assess potential population decline and trends of suitable habitat across its range. Demographic and other fine-scale data are needed to assess population trends.

This species is collected for scientific research with no other documented direct human use. Puncelia missouriensis is used as an element-based bioindicator of air pollution in central and southern parts of the eastern United States of America (Will-Wolf et al. 2017).