Type: Ecuador, Galapagos Islands, San Cristóbal, near Tortugueria Cerro Colorada, on lava cliff, 130 m alt., 2 June 2005, A. Aptroot 63419 (CDS 30174–holotype; ABL–isotype).
Etymology. The small branches are relatively fragile and easily break of at the base.
Thallus dull, shrubby, up to 3 cm in diam., upright or irregularly spreading, fragile, with very few branches, rather pale grey and resembling a small Roccella; branches terete, up to ca. 1 mm in diam, but usually much thinner; soralia discrete, capitate, whitish, up to ca. 1 mm in diam; apothecia and pycnidia unknown; medulla K-, UV- (no substances) or K+ pinkish, UV- (sekikaic acid); cortex with usnic acid and often atranorin.
Because of its similarity to Roccella, the small, pale thalli with terete, fragile branches can hardly be confused with any other Ramalina species in the Galapagos. Although it is very distinct, the small species may easily be overlooked.
Selected specimens examined. Ecuador: Galápagos: Pinzón Island, along the trail going up from Playa Escondida, 0˚ 36’ 10” S, 90˚ 40’ 1” W, alt. 254 m, arid zone with Prosopis juliflora, Alternanthera filifolia, Maytenus octogona, and Croton scouleri, on rock, basalt, 16 ii 2006, A. Aptroot 64127 (CDS no. 30689); San Cristóbal Island, near Tortugueria Cerro Colorada, 0˚ 54’ 56” S, 89˚ 26’ 18” W, alt. 130 m, on rock (basalt lava), 02 vi 2005, A. Aptroot 63419 (CDS no. 30174); rim of crater to the NW of Media Luna, inland from the NW-coast, 0˚ 43’ 51” S, 89˚ 18’ 55” W, alt. 149 m, lower transition zone; basalt cliffs of inner and outer crater rim with scarce vegetation, on rock, S-exposed overhang of cliff on top of crater rim; shaded, wind- and rain-sheltered, 22 iv 2007, F. Bungartz 6306 (CDS no. 34518).
from: Aptroot, A. & Bungartz, F. (2007) The lichen genus Ramalina on the Galapagos. The Lichenologist39(6): 519-542.
Ramalina fragilis is the rarest one of four endemic Galapagos species in the genus Ramalina. In the Galapagos this genus is unusually species diverse and extremely abundant on shrubs and trees from the coastal zone into the transition zone. Trees and shrubs from afar often have a greenish-yellow colour because they are abundantly draped by usnic-acid coloured Ramalina species. Ramalina fragilis is, however, one of the few rock-dwelling Galapagos Ramalina. It is in many respects unusual: a pale species that easily breaks apart (thus its name). Growing on rock, particularly the coastal sites are susceptible to flash floods during El Niño years and the fragile thalli offer little resistance against erosion. Some sites at very low altitude, in the immediate vicinity of the sea and may also be subject to exceptionally high tides, and these habitats may be affected by sea-level rise. Future declines in the population size, area of occupancy, and habitat quality of up to 40% over the next 45 years (three generations) are suspected due to extreme El Niño events, thus the species is assessed as Vulnerable (A3c).
Assessor/s: Bungartz, F. & Parrinello, C.; Reviewer/s: Allen, J. & Vargas, R.; Contributor/s: Salinas, N. & Dal Forno; M. Facilitator(s) and Compiler(s): Lymbery, C. & Allen, J.
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Special note from the Author of the assessment:
Acknowledgments- Author thanks the Charles Darwin Foundation and the Galapagos National Park as well as a grant from the Mohamed Bin Zayed Species Conservation Fund (project 152510692) and the National Science Foundation (DEB 0841405), who all made this work possible.
Find out more about the IUCN Red List Categories and Criteriahere.