Thelomma carolinianum is distinctive crustose lichen that has been lost from 72% of the total known sites (inferred from a comparison of historical vs. modern (pre-1990 vs. post-1990) occurrence data supported by voucher specimens), together with a 68% loss of Area of Occupancy and 95% loss of Extent of Occurrence. The causes of this reduction are considered to be the large scale degradation and loss of habitat, as well as loss of suitable substrates, 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. Therefore, it is listed as Endangered under criteria A2bce+4bce; B2ab(i,ii,iii,v).
Assessor/s: Lendemer, J.; Reviewer/s: Scheidegger, C. & McMullin, T.; Contributor(s): Weerakoon, G.; Facilitator(s) and Compiler(s): Chandler, A. & Allen, J.
Bachman, S., Moat, J., Hill, A.W., de la Torre, J. & Scott, B. (2011) Supporting Red List threatassessments with GeoCAT: geospatial conservation assessment tool. In: V. Smith and L. Penev (eds) e-Infrastructures for data publishing in biodiversity science. Zookeys150: 117–126.
Drummond, M.A. & Loveland, T.R. (2010) Land-use pressure and a transition to forest-cover loss in theeastern United States. BioScience60(4): 286-298.
IUCN. 2020. The IUCN Red List of Threatened Species. Version 2020-3. Available at: www.iucnredlist.org. (Accessed: 10 December 2020).
Napton, D.E., Auch, R.F., Headley, R. & Taylor, J.L. (2010) Land changes and their driving forces in thesoutheastern United States. Regional Environmental Change10(1): 37-53.
Tibell, L. (1976) The genus Thelomma. Botaniska Notiser129: 221-249.
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TYPE. UNITED STATES. SOUTH CAROLINA [Beaufort County]. “on old logs of Cedar, Bluffton, South Carolina (Dr. J.H. Mellichamp)” (Tuckerman 1872; FH, lectotype selected in Tibell 1976; US 00067721, isotype; NY 1611655, possible isotype;).
Description. Lichenized fungus.
Thallus crustose, continuous to areolate, pale to yellowish, smooth to verrucose. Cortex 30-35 μm thick, densely interspersed with granular crystals; medulla also with crystals. Photobiont chlorococcoid alga. Ascomata maezedia immersed in verrucae, 0.5-1.5 mm diam.; maezedium flat to slightly convex, black, epruinose; margin indistinct. Exciple brown-black; hymenium 55-75 μm high, I+ dark blue. Asci pyriform, 35-40 x 14-16 μm with a long stalk; 8-spored. Ascospores brown, ellipsoid, 2-celled, slightly constricted at septum, 12-18 x 7-9 μm; surface slightly uneven.
Chemistry. Thallus K+ deep red, C-, PD+ yellow; xanthone and norstictic acid.
Substrate and Habitat. Lignicolous on wood or decorticated trunks.
Distribution. Southeastern North America, mostly in Florida; in North Carolina its presence is questionable, represented by one historical specimen (Calkins s.n., s.d, MICH 131157) that lacks location information below state and needs to be verified.
Fink, B. (1935) The Lichen Flora of the United States. University of Michigan Press, Ann Arbor. 426 pp. (description as Cyphelilum carolinianum).
Tibell, L. (1976) The genus Thelomma. Bot. Notiser129: 221-249 (description as Thelomma carolinianum).
Tuckerman, E. (1872) Genera Lichenum: an arrangement of the North America lichens. 281 pp. (original description as Acolium carolinianum).