Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2004. Lichen Flora of the Greater Sonoran Desert Region. Vol 2.
Life habit: lichenized Thallus: coherent, granular or verrucose, soon compacted into a chinky crust, attached by the whole lower surface surface: white or pale gray cortex: 20-30 µm thick, hyaline, granular, composed of decaying photobiont cells and granular crystals forming a phenocortex photobiont: a chlorococcoid green alga; algal layer: 40-80 µm thick, continuous medulla: loose, gray, floccose; hyphae: strongly articulate, arranged "centrifugally" Apothecia: 0.5-0.8 mm in diam., about the same in height, cylindrical, lecanorine, sessile mazaedium: +protruded, black, olive-ochre-yellow to yellow-green pruinose thalline margin: with abundant light yellow or ochre-yellow pigment exciple: dark brown to black, in the upper part lined with yellow crystals on the surface, thick only at the base, with a network of brown hyphae reaching deep into the medulla of the thallus, thin above hymenium: paraphyses: forming a dense tissue, at first c. 2 µm wide, enclosing the spores like a halo, then becoming up to 6-8 µm wide with shorter and strongly pigmented cells asci: soon disintegrating, 38-48 x 4-5 µm, 8-spored ascospores: brown, 1-septate (but septum +obscured by the enclosing hyphae), rounded, obtuse at the poles, short-ellipsoid, with pseudoparenchymatous, many- and small-celled coat of enclosing hyphae (appearing highly "blistered"), (15-)19-26 x (7-)10-14 µm, including the hyphal coat (20-)35-44 x (16-)19-26(-30) µm; hyphal coat: pseudoparenchymatous, multi-celled, formed from the surrounding paraphyses; cells of hyphal coat: thin-walled and lobed-crenate, overlapping, the central cells highly vacuolated, with walls 1-2 µm thick Conidiomata: unknown Spot tests: thallus K-, C-, KC-, P- Secondary metabolites: containing calycin in the apothecial margin and in the mazaedium. Substrate and ecology: on soil and animal pellets (e.g. rabbit) World distribution: western North America, particularly arid intermountain areas Sonoran distribution: southern California. Notes: Texosporium sancti-jacobi is rather rare. It is easily distinguished from Cyphelium and Thelomma by the unusual spore structure (pseudoparenchymatous 'episporium').
Texosporium sancti-jacobi is a distinctive, late succession, soil-dwelling species endemic to arid regions of the western United States of America. Numerous threats have led to reduction in its habitat quality and extent of occurrence, area of occupancy, and the number of mature individuals. While its extent ofoccurrence is large, its area of occupancy is small (minimum AOO = 356 km2). Therefore, it is listed as Endangered, B2ab(ii,iii,iv,v).
Assessor/s: Stone, D., Root, H., Hollinger, J., Rosentreter, R., Chandler, A. & Allen, J.; Reviewer/s: Lendemer, J.; Facilitator(s) andCompiler(s): Allen, J. & Chandler, A.
Concostrina-Zubiri, L., Huber-Sannwald, E. Martinez, I., Flores, J.L.F., Reyes-Agüero, J.A., Escudero, A. & Belnap, J. (2014) Biological soil crusts across disturbance-recovery scenarios: effects of grazing regime oncommunity dynamics. Ecological Applications24(7): 1863-1877.
Condon, L.A., Pietrasiak, N. Rosentreter, R. & Pyke, D.A. (2019) Passive restoration of vegetation and biological soil crusts following 80 years of exclusion from grazing across the Great Basin. Restoration Ecology28: 1-11.
Dettweiler-Robinson, E., Ponzetti, J.M. & Bakker, J.D. (2013) Long-term changes in biological soil crust cover and composition. Ecological Processes2(5): 1-10.
IUCN (2020) The IUCN Red List of Threatened Species. Version 2020-3. Available at: www.iucnredlist.org. (Accessed: 10 December 2020).
Jimenez, A.A., Huger-Sannwald, E., Belnap, J., Smart, D.R. & Arredondo, M.J.T. (2009) Biological soil crusts exhibit a dynamic response to seasonal rain and release from grazing with implications for soilstability. Journal of Arid Environments73(12): 1158-1169.
Kaltenecker, J.H., Wicklow-Howard, M.C. & Rosentreter, R. (1999) Biological Soil Crusts in Three Sagebrush Communities Recovering from a Century of Livestock Trampling. USDA Forest Service Proceedings RMRS-P-11.
McCune, B. & Rosentreter, R. (2007) Biotic Soil Crust Lichens of the Columbia Basin. Northwest Lichenologists, Corvallis.
Muscha, J.M. & Hild, A.L. (2006) Biological soil crusts in grazed and ungrazed Wyoming sagebrush steppe. Journal of Arid Environments 67(2): 195-207.
Riefner, R.E., Jr. & Rosentreter, R. (2004) The distribution and ecology of Texosporiumin Southern California. Madroño51(3): 326-330.
Rosentreter, R., Bowker, M. & Belnap, J. (2007) A Field Guide to Biological Soil Crusts of Western U.S.Drylands (Common Lichens and Bryophytes). U.S. Government Printing Office, Denver, CO.
Stone, D., Hardman, A. & Beck, K. (2018) Going for the Gold: A Search for Texosporium sancti-jacobi in Washington. Spokane District Bureau of Land Management (BLM), Spokane, WA.
Tabeni, S., Garibotti, I.A., Pissolito, C. & Aranibar, J.N. (2014) Grazing effects on biological soil crusts and their interaction with shrubs and grasses in an arid rangeland. Journal of Vegetation25(6): 1417-1425.
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