Galapagos Species Database
The Galapagos Species Database shares the information about the species from our Natural History Collections.
Usnea galapagona
rumibarba, liquen de barba, barba de la piedra, barbas de viejo, Beard lichen
Thallus fruticose, up to 8 cm long, erect and strongly shrubby, often with several attachment points. Base concolorous with thallus, usually with a reddish tinge. Branching distinctly anisotomic-dichotomous. Branches irregular to tapering, not constricted at their attachment point. Section of branches terete to slightly flattened or ridged. Terminal branches with few divisions and thickened at the tips. Fibrils few or absent. Papillae hemispherical, often numerous. Soralia minute, often aggregating in small packs or fusing and thus looking like a large single soralium, developing on top of papillae or directly on the cortex ad initio, remaining plane with a distinct cortical margin, rarely becoming slightly stipitate or efflorescent, but never excavating. Isidiomorphs present, very small. Apothecia not seen. Cortex thick (15.5–19.5% of branch width, n = 10), very hard and vitreous in longitudinal section of branch. Medulla compact, usually very thin and almost indistinct (3–4.5%), rarely thicker (up to 10%) close to the base. Axis very thick (54.5–62%). Chemistry: Medulla K–, C–, P–; usnic acid and an unknown compound reacting UV+ green after charring (RF classes: solvent A = 6; B = 3; C = 5).
Usnea galapagona is characterized by anisotomic-dichotomous branching, terminal branches with few divisions, the absence of fibrils and the minute soralia developing from low papillae or on the cortex of branches, often aggregating in packs or fusing. Anatomy in longitudinal section of branch is very characteristic, with a thick, very hard and vitreous cortex, a thick axis and a very thin, almost indistinct medulla. TLC analysis revealed the presence of a new unknown substance in the medulla, reacting UV+ green after charring. The cortex of U. subscabrosa Motyka (Herrera-Campos et al.1998) is similar to U. galapagona, but the former species is pendulous, with a very different morphology, chemistry and ecology.
Domain
Eukaryota
Kingdom
Fungi
Phylum
Ascomycota
Class
Lecanoromycetes
Order
Lecanorales
Family
Parmeliaceae
Genus
Usnea
Species
galapagona
Taxon category: Accepted
Type: Ecuador. Galapagos: Isla Sán Cristóbal, Cerro Mundo, at the top of the rock cliffs on the S side close to the summit, 00°53’S, 89°34’W, 282 m, transition zone with Bursera graveolens, Croton scouleriand Jasminocereus thouarsii, on Jasminocereus thouarsii on the ridge, August 2008, Clerc & Truong 08-405(holotype CDS, isotypes G, CMA: 16/3/61.5; chemistry: usnic acid, unknown medullary metabolite reacting UV+ green after charring).
Origin: Endemic
Map of specimen collection localities or observation records for this species in our collections database.
Distribution: Endemic to the Galápagos Islands, so far known from Isabela, Sán Cristóbal and Santa Cruz Islands. This species usually grows on exposed habitats, for instance along ridges or on the slopes of the volcan’s crater. It was found in the transition vegetation zone, seldom in the arid and humid zones. Su
- Herrera-Campos, M. Clerc, P., Nash III, T.H. (1998) Pendulous species of Usnea from the temperate forests in Mexico The Bryologist 101: 303–329.
- Lumbsch, H.T. Ahti, T., Altermann, S., Amo de Paz, G., Aptroot, A., Arup, U., Bárcenas Peña, A., Bawingan, P.A., Benatti, M.N., Betancourt, L., Björk, C.R., Boonpragob, K., Brand, M., Bungartz, F., Cáceres, M.E.S., Candan, M., Chaves, J.L., Clerc, P., Common, R., Coppins, B.J., Crespo, A., Dal Forno, M., Divakar, P.K., Duya, M.V., Elix, J.A., Elvebakk, A.V., Fankhauser, J., Farkas, E., Ferraro, I.L., Fischer, E., Galloway, D.J., Gaya, E., Giralt, M., Goward, T., Grube, M., Hafellner, J., Hernández M., J.E., De los Ángeles Herrera Campos, M., Kalb, K., Kärnefelt, I., Kantvilas, G., Killmann, D., Kirika, P., Knudsen, K., Komposch, H., Kondratyuk, S., Lawrey, J.D., Mangold, A., Marcelli, M.P., McCune, B., Messuti, M.I., Michlig, A., Miranda Gonzáles, R., Moncada, B., Naikatini, A., Nelsen, M.P., Øvstedal, D.O., Palice, Z., Papong, K., Parnmen, S., Pérez-Ortega, S., Printzen, C., Rico, V.J., Robayo, J., Rosabal, D., Ruprecht, U., Salazar Allen, N., Sancho, L., Santos de Jesus, L., Santos Vieira, T., Schultz, M., Seaward, M.D.R., Sérusiaux, E., Schmitt, I., Sipman, H.J.M., Sohrabi, M., Søchting, U., Søgaard, M.Z., Sparrius, L.B., Spielmann, A., Spribille, T., Sutjaritturakan, J., Thammathaworn, A., Thor, G., Thüs, H., Timdal, E., Truong, C., Türk, R., Umaña Tenorio, L., Upreti, D.K., Van den Boom, P., Vivas Rebuelta, M., Wedin, M., Will-Wolf, S., Wirth, V., Wirtz, N., Yahr, R., Yeshitela, K., Ziemmeck, F., Lücking, R. (2010) One hundred new species of lichenized fungi: a signature of undiscovered global diversity. Phytotaxa 18: 1-127.
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This page should be cited as follows:
"Galapagos Species Database, Usnea galapagona", dataZone. Charles Darwin Foundation, https://datazone.darwinfoundation.org/en/checklist/?species=4129. Accessed 4 November 2026.