Identification Information: From Brodo (1986): Thallus dull yellowish white grading into light brown and reddish-brown at the more exposed tips; rarely shades of olive-gray in places ... 3-5 cm long; main branching isotomic toanisotomic-dichotomous, with more-or-less perpendicular spinulose branches developing from splits inthe thallus; branches splitting lengthwise and opening into rather wide linear soralia filled with spinulose isidia and spinules, often with brown tips; main branches 0.3 - 0.5mm wide ... very brittle ... . Apothecia and pycnidia not seen.
This species is assessed as Critically Endangered (CR) on the basis of it having a very narrow distribution (10 km diameter area), correlating to an extent of occurrence of less than 100 km², and an area ofoccupancy of just 8 km². A continuing decline in the extent of occurrence, and the number of mature individuals is reported, and it is considered that this species severely fragmented and found in 1-4 locations based on the threats of development and changes to the fire regimes.
Assessor/s: McMullin, T., Allen, J. & Lendemer, J.; Reviewer/s: Scheidegger, C.; Contributor(s): Aptroot, A., Dahlberg, A., Weerakoon, G., Perez-Ortega, S & Spribille, T..
Brodo, IM. (1986) A new species of the lichen genus Sulcaria (Ascomycotina, Alectoriaceae) from California. Mycotaxon27: 113-117.
IUCN (2019) The IUCN Red List of Threatened Species. Version 2019-3. Available at: www.iucnredlist.org. (Accessed: 10 December 2019).
Carlberg, T. & K. Knudsen (2007) Sulcaria isidiifera, sponsorship for the CALS Conservation Committee. Bulletin of the California Lichen Society14(2): 45-47.
Find out more about the IUCN Red List Categories and Criteriahere.