• 1Proposed
  • 2Under Assessment
  • 3Preliminary Assessed
  • 4Assessed
  • 5Published

Rinodina chrysomelaena Tuck.

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Scientific name
Rinodina chrysomelaena
Common names
IUCN Specialist Group
Assessment status
Proposed by
James Lendemer
James Lendemer
Comments etc.
Jessica Allen, Anders Dahlberg

Assessment Notes

Taxonomic notes

Why suggested for a Global Red List Assessment?


Authors: James C. Lendemer, Jessica Allen, Troy McMullin, Christoph Scheidegger, Erin Tripp

Common Name: Muhlenberg’s Smile
Current Scientific Name: Rinodina chrysomelaena (Ach.) Tuck.
Synonyms: None.

Proposed Status: Critically Endangered B1a,b(i,ii,iii,iv); B2a,b(i,ii,iii,iv); C2ai,ii
EOO: 806,370.175 km2 (historical) / 0 km2 (presumed extant) / >95% loss
AOO: 36.000 km2 (historical) / 8.000 km2 (presumed extant) / 77.77% loss
# of Documented populations: 11 (total): 9 (historical) / 2 (presumed extant) / 81%

Assessment Synopsis. – Rinodina chrysomelaena is a bright yellow crustose lichen occurred on non-calcareous rocks at scattered locations in the Appalachian Mountains of eastern North America and Mexican Highlands of Oaxaca, Mexico. Substantial declines have been documented, including a 77% loss of populations and overall reduction of >95% from the total historical range. Increased acquisition and protection of suitable habitat, monitoring of existing populations, and raising awareness of the species are recommended conservation measures for the species.

Distinguishing Traits. – The species can be recognized by its occurrence on non-calcareous rocks and bright yellow thallus with rounded dark purple-black disc-like fruiting bodes.


Distribution and Ecology. – Rinodina chrysomelaena is restricted to the Appalachian Mountains of eastern North America (Massachusetts south to Georgia) and Mexican Highlands of Oaxaca, Mexico. It was historically known from a small number of scattered locations where it grew on non-calcareous rocks. Precise ecological data are lacking for all historical populations. The two extant populations occur on somewhat shaded non-calcareous rocks in humid habitats associated with waterways and waterfalls.
Online databases (CNALH) report a voucher from “mountains of western” North Carolina and from Colorado Springs, Colorado. The former voucher lacks precise locality data, was not included in modern treatments of the species (Lendemer & Sheard 2006, Sheard 2010) and is considered to be questionable. The record from Colorado is well outside the accepted geographic range of the species, includes an “?” indicating the identification was not certain, and was not annotated or cited by relevant taxonomic authorities. It is treated as an erroneous report and excluded from EOO/AOO calculations here.

Status of Populations – The rarity of Rinodina chrysomelaena appears to be a modern phenomenon, as it was noted to be common at one locality where it occurred in 1932 but is no longer found (Degelius 1941, Sheard 2010). The species was collected by many 19th and early 20th century lichenologists, but is rarely collected now, illustrating that it was once widespread but has now been extirpated (Lendemer & Sheard 2006, Sheard 2010). None of the nine populations documented prior to 1990 have been relocated, and of the two populations discovered post-1990 (both in 2010) only one is located within a protected area (Great Smoky Mountains National Park). The majority of locations where the species was found historically are now developed (e.g., the metro-regions of Boston, Chattanooga and Philadelphia). The two known extant locations are small in size and isolated within a relatively small geographic area, each with fewer than <50 individuals. The very few documented extant populations is not due to lack of field work in the region. Extensive post-1990 fieldwork has been conducted within the range of the species by multiple experts (Massachusetts: E. Lay, E. Kneiper, P. May); Georgia: S.Q. Beeching & M. Hodges; Pennsylvania: J.C. Lendemer; southern Appalachians: J. Allen, J.C. Lendemer, T. Tønsberg, E. Tripp).

Protected Status. – None.

Threats. – The cause of the large scale extirpation of Rinodina chrysomelaena was not documented at the time it occurred, however it is likely attributable to the large scale loss and degradation of suitable habitat throughout its range historically (Drummond & Loveland 2010, Napton et al. 2010). The lack of protection of the species by state, federal, and international legislation is a further threat to the species.

Explanation of Proposed Rank. – This species merits ranking as Critically Endangered: B1a,b(i,ii,iii,iv) and B2a,b(i,ii,iii,iv). This rank is based on the pre-1990 vs. post-1990 reduction of EOO to <100 km2, 77% reduction in AOO (8.000 km2 post-1990), and the extirpation of all known historical populations (balanced by discovery of two extant populations). In both cases the ranking is supported by 1) the extensive fragmentation of natural habitats and populations (both historical and modern), 2) severely fragmented, small number of extant populations (2), 3) decline in EOO, AOO, and total number of populations inferred from documented occurrences, and 4) historical and ongoing habitat degradation. The species also meets the criteria for Critically Endangered C2ai,ii based on the small number of mature individuals, the continuing decline in the number of locations, and the small number of mature individuals in the sole remaining subpopulation together with the fact that 100% of the remaining individuals exist within one subpopulation.
The species also meets Endangered under criterion A2c. The rank is based on the documented losses in number of populations as well as reductions of EOO and AOO. The causes of this reduction are unknown, but inferred to be the large scale degradation and loss of habitats throughout the range of the species. These losses have occurred in the past, are ongoing at present at smaller scales, and will likely continue in the future.

Conservation Recommendations. – Monitoring of all extant populations is required to determine whether the species has stabilized or is still in decline. Increased acquisition of suitable habitat, and increased protections for suitable habitat already within management units is also needed. Study of the potential reintroduction into formally occupied areas should also be considered, but balanced by the extreme rarity of the species and the small size of extant populations to serve as source material. Increased education about the species, its ecology, and how it could be conserved would also be highly beneficial. 

Literature Cited.

Degelius, G N 1941: Contributions to the Lichen flora of North America II. The lichen flora of the Great Smoky Mountains. - Arkiv för Botanik\Ark. Bot. 30A, Nr. 3: 1-80.
Drummond, M.A., Loveland T.R., 2010, Land-use pressure and a transition to forest-cover loss in the eastern United States, Bioscience, v.60,4, pp.286-298
Napton, D.E., Auch, R.F., Headley, R., Taylor, J.L., 2010, Land changes and their driving forces in the Southeastern United States, Regional Environmental Change, v.10,1, pp.37-53
Lendemer, J. C./ Sheard, J. W. 2006: The typification and distribution of Rinodina chrysomelaena (Physciaceae), a rare eastern North American lichen. - The Bryologist 109(4): 562-565.
J. W. Sheard 2010: The Lichen Genus Rinodina (Lecanoromycetidae, Physciaceae) in North America, North of Mexico. - National Research Council of Canada, NRC Research Press, Ottawa. 246 pp.

This is an easily recognized crustose lichen endemic to North America (including Mexico) that is considered to be extirpated from more than 90% of its historical range. Extensive efforts to relocate historical populations have failed and only two extant populations are known, both occurring in a highly limited geographic area.

Geographic range

Historical range: Appalachian Mountains of eastern United States and Mexican Highlands (Oaxaca). Current known range: geographically limited region of the southern Appalachian Mountains of western North Carolina and northern Georgia.

Population and Trends

Demographic studies of extant populations are needed to assess and monitor populations sizes. Species is presumed extirpated from much of its range, remaining extant populations small in size and number of individuals.

Population Trend:

Habitat and Ecology

Habitat and ecological data from historical collections are limited, however the extant populations occurs on non-calcareous rocks in shaded forests in high humidity microhabitats especially near waterfalls.

Temperate Forest


This species is threatened by transportation corridors increasing air pollution, and climatically suitable habitats shifting with climate change. Recreation may be an additional threat.

Residential & commercial developmentTourism & recreation areasTransportation & service corridorsRoads & railroadsUtility & service linesHuman intrusions & disturbanceRecreational activitiesNatural system modificationsTrend Unknown/UnrecordedDams & water management/useDams (size unknown)Climate change & severe weatherHabitat shifting & alterationDroughtsStorms & flooding

Conservation Actions

Known remaining populations are in national park or national forest areas. However these are areas with substantial recreation. In addition to assuring the populations are not damaged by recreation the following actions could be taken: educating and training land managers and local botanists to identify the species so we can monitor its health, federally listing the species as endangered in the United States, and improving air quality regulation.

Land/water protectionSite/area protectionResource & habitat protectionLand/water managementSite/area managementSpecies recoveryEducation & awarenessFormal educationTrainingAwareness & communicationsLaw & policyLegislationNational level

Research needed

The distribution of this species is very well understood. It is well documented has having been extirpated from much of its range. Further searching of suitable habitats should be undertaken, although these have been unsuccessful to date outside of the area were known populations are extant. Further research that will aid in the conservation of this species includes population assessments and monitoring, population genetics studies, and ecological studies that incorporate threats to the species. Additionally, a species recovery plan needs to be written.

ResearchPopulation size, distribution & trendsLife history & ecologyThreatsActionsConservation PlanningSpecies Action/Recovery PlanMonitoringPopulation trendsHabitat trends

Use and Trade


Lendemer, J.C., R.C. Harris and E.A. Tripp. 2013. The lichens and allied fungi of Great Smoky Mountains National Park: an annotated checklist with comprehensive keys. Memoirs of The New York Botanical Garden 104: i-viii, 1-152 [effectively published in print 09 January 2013].

Lendemer, J.C., E. Tripp and J.W. Sheard. 2014. A review of Rinodina (Physciaceae) in Great Smoky Mountains National Park highlights the growing significance of this “island of biodiversity” in eastern North America. The Bryologist 117(3): 259-281.

Lendemer, J. C./ Sheard, J. W. 2006: The typification and distribution of Rinodina chrysomelaena (Physciaceae), a rare eastern North American lichen. - The Bryologist 109(4): 562-565.

J. W. Sheard 2010: The Lichen Genus Rinodina (Lecanoromycetidae, Physciaceae) in North America, North of Mexico. - National Research Council of Canada, NRC Research Press, Ottawa. 246 pp.

Known distribution - countries

Regional Population and Trends

Country Trend Redlisted