Niebla and Vermilacinia (Ramalinaceae) from California and Baja California.  
Spjut, R.W., 1996. ISSN 0833-1475, 208 pp.  
Sida, Botanical Miscellany 14. Botanical Research Institute of Texas, Inc.

Evolution and diversification of Niebla
Steve Leavitt et al., Baja California, Dec 2016

Jorna J, J Linde, P Searle, A Jackson, M-E Nielsen, M Nate, N Saxton, F Grewe, M de los Angeles Herrera-Campos, R Spjut, H Wu, B Ho, S Leavitt, T Lumbsch.  Species boundaries in the messy middle -- testing the hypothesis of micro-endemism in a recently diverged lineage of coastal fog desert lichen fungi. Ecology and Evolution. Published Online: 20 Dec 2021.  https://onlinelibrary.wiley.com/doi/full/10.1002/ece3.8467.

Leavitt et al. 16-775. Niebla sp. as det. by R. Spjut. Southwest of San Quintín in the Punta Mazo Reserve (managed by Terra Peninsular), on Monte Ceniza, west-facing slope. Referred to N. isidiosa in Jorna et al. (2021).

Niebla isidiosa as det. by R. Spjut. Southwest of San Quintín in the Punta Mazo Reserve (managed by Terra Peninsular), on E side of Bahía Falsa, shoreline, boulder outcrops, Leavitt et al. 16-953, Dec 2016. Note initially det. by R. Spjut without TLC data, referred to as N. aff. isidiosa (Jorna et al. (2021).

     Niebla isidiosa is a fruticose lichen endemic to coastal areas of Baja California, on the mainland near San San Quintín and on Isla Guadalupe. The species is characterized by a rigid thallus divided into broad sublinear branches with a reticulately ridged cortex producing abundant isidia along the cortical ridges, by the branches abruptly recurved near branch tips, and by containing divaricatic acid.  It resembles N. caespitosa, in contrast to another divaricatic acid isidiate species, N. isidiaescens, that resembles N. flagelliforma by the terminal branches recurved near to apex as seen in the type and other specimens collected on the Vizcaíno Peninsula. They  differ from N. isidiosa in their more cylindrical shape with closely reticulate ridges on terminal branches. However, other specimens of N. isidiaescens collected on Mesa Camacho in the Northern Vizcaíno Desert differ in having longer flexuous coiled branches; they probably belong to another isidiate species with divaricatic acid.

     Niebla isidiosa was discovered on Isla Guadalupe by Palmer in 1875.  Elix and McCarthy later reported they found it on the island (website, March 2005, with reference to J. A. Elix. & P. M. McCarthy, 1998: Catalogue of the lichens of the smaller Pacific Islands, Bibliotheca Lichenologica 70, 1 - 361). A more recent collection by Leavitt et al., 16-953, is from the Baja California peninsula near San Quintín.  

     Another specimen collected by Leavitt et al.,16-775, identified Niebla sp., shown above, was collected on the west slope of a volcano (Monte Ceniza).  It differs from N. isidiosa by the more fragile thallus branches appearing to disarticulate at various intervals, by the cylindrical branch shape, recessed areoles between cortical ridges, branches tapering to a pointed apex, and producing coralloid isidia.  Uniting the specimens under N. isidiosa is supported by DNA  in Jorna et al. (2021, Fig. 5); however, there are many other examples where thalli appear similar but not supported by DNA.  In a limited selection of 40 specimens for evaluating species delimitation in the genus Niebla  (Jorna et al. 2021), N. isidiosa was shown sister to N. flagelliforma, both in clade sister to a sekikaic acid clade of N. cornea represented by four specimens, two from the Channel Islands, the other two from the Punta Mazo Reserve near San Quintín.

Additional References: See Niebla.