Niebla testudinaria

The World Botanical Associates Web Page
Prepared by Richard W. Spjut
April 2003, Nov. 2005, Sep 2012
Additional images and text May 2017, Dec 2021

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.

Evolutionary history of coastal species of fog lichen genera
, Ramalina and Vermilacinia
Emmanuel Sérusiaux & Richard  Spjut
Baja California, Jan-Feb 2016

Spjut R, Simon A, Guissard M, Magain N, Sérusiaux E. The fruticose genera in the Ramalinaceae (Ascomycota, Lecanoromycetes): their diversity and evolutionary history.  MycoKeys. 2020 Oct 30;74:109-110]. MycoKeys. 2020;73:1-68. Published 2020 Sep 11. doi:10.3897/mycokeys.73.47287

Evolution and diversification of Niebla
Steven 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.


Southwest of San Quintín in the Punta Mazo Reserve on volcanic slopes of Volcan Sudoeste
Leavitt et al. 16-703, Dec 2016


North of El Rosario along the Transpeninsular Hwy 1, small ridgeline west of highway dominated by euphorbs and small rocks.  Leavitt et al. 16-829, Dec 2016

Along Punta San Telmo road on cacti-dominated hillside.  Leavitt et al. 16-1166, Dec 2016

N of Punta San Rosallilita, Canyon de San Andrés, Spjut & Sérusiaux 17114, Jan 2016.

testudinaria-9027.jpg (83967 bytes)

Just S of Tijuana near Rosarito, Spjut & Marin 9027T.  Thallus immature
May 1985.

Isla San Martín, BCN
Moran 1055 (COLO)


San Luis Obispo Co., CA. Bratt 3212


La Misíón, between Tijuana and Ensenada.
Weber & Santesson
(COLO: 43035)


Santa Cruz Is., CA
Bratt 6431



Santa Barbara  Co.,
Santa Ynez Mts.
Bratt 7202



San Mateo Co. CA
Howe 92 (COLO:13353)

Monterrey, CA
Herre 256


Santa Cruz Island
Bratt 6427


Lectotype: Menzies,  Monterrey, CA (H-NYL 37213, H)


Pt Lobos State Park
Monterrey Co., CA
Chris Parrish 69357
Chris Parrish 151691

Pt Lobos State Park
Monterrey Co., CA
CalPhotos: Ron Wolf



     Niebla testudinaria is a fruticose lichen found most often on rocks along the California coast and off shore islands within the maritime coastal sage chaparral, ranging from Isla Guadalupe and Isla San Martín (just off the coast of San Quintín) to the Channel Islands, and on the California mainland from near Tijuana to Marin Co.  It appears locally common in Point Lobos State Park, often with Vermilacinia procera and V. laevigata, judging from review of internet images and herbarium material. It was locally common just south of Tijuana near Rosarito on talus-like rubble in association with Vermilacinia combeoides and V. pumila, an area that has undergone extensive real estate development. 

     The epithet, testudinaria, provided by Nylander, suggests that the species was recognized for the reticulate pattern on the cortical surface, like that seen on tortoise shells, especially thalli with dilated branch segments. The varicose vein-like ribbing within a relatively thick cortex (>75 µm), along with the presence of divaricatic acid, distinguishes N. testudinaria from related species; Niebla homalea, for example, has relatively narrow linear branches with a glossier cortex transversely cracked at various intervals.  Another characteristic feature of N. testudinaria is that branches frequently divide ± equally dichotomous, or digitately, especially arching branches, in contrast to unequal mostly linear branching in N. homalea.

     The reticulate ridging that characterizes Niebla testudinaria is seen in thalli with narrow to irregularly widened branches. The narrower parts appear prismatic in cross-section, the wider parts often expand and flattened like the palm of a hand from which ± isodichtomous or isotrichotomous (isotomic) branchlets arise.   Relatively short thalli, wider than tall (e.g., Moran 1055 from Isla San Martín, Leavitt et al. 16-1166) show resemblance to N. caespitosa, which differs by its relatively thinner cortex as evident by more sharply defined cortical ridges, and by irregularly lacerated branches. Bratt 2303 from Santa Cruz Island (N. casepitosa), which might be referred to N. testudinaria, was distinguished by its thinner cortex; otherwise, it is similar to Spjut & Sérusiaux 17114, Leavitt et al.  16-829, 16-703

     DNA phylogeny of N. testudinaria, as with most other depside species, reveals it in different subclades, or microclades; however, statistical analyses (BPP, Stacey) for three specimens indicated only one species. Specimens collected by Leavitt et al. were not included in Jorna et al. (2021).

     The character feature of reticulate cortical ribbing of Niebla testudinaria appears plesiomorphic to various subtaxa that might be formally named. This is exemplified in the following dendrogram.

      The morphological features of the "variants" are outlined above in contrast to distinguishing features of N. eburnea and its 'variants' (or morphs).  The N. testudinaria variants are each discussed below by name for the species they appear most similar to and to locations where collected.  Images are shown above for most "variants" discussed. 

     The N. testudinaria 'variants' include: (1) a widely distributed 'Caespitoid' variant, similar to N. caespitosa by the dilated branches, (2) a 'Haleoid' variant, similar to N. halei by the more densely branched thallus with narrow prismatic branches, occurring on Santa Cruz Is. and nearby Santa Ynez Mts., (3)  a 'Homaleoid' variant, similar to N. homalea in the frequent twisting of narrow branches, found on Santa Cruz Island and the California mainland, (4) a 'Dissectoid' variant on Isla Guadalupe (Spjut 1996, Fig 38.5).       

     The 'Caespitoid' variant of N. testudinaria—characterized by dilated branches—is similar to N. caespitosa, a species found in Baja California and Channel Islands, distinguished from N. testudinaria by its relatively thinner cortex and ragged thallus margins.  Generally, one does not need to measure the cortex. The relatively thin-skinned (cortex) thalli of N. caespitosa are generally more crinkled  (crispate) like tortilla chips when dry.  Niebla flabellata is also similar in cortical and marginal features, but has salazinic acid instead of divaricatic acid; it is found mostly outside the range of N. testudinaria; however, N. caespitosa and N. flabellata occur in close association in Baja California where they are best distinguished by their lichen substances.  Examples of the 'Caespitoid' variant of N. testudinaria are shown for specimens collected from Isla San Martín, Rosarito near Tijuana and from Morro Rock in San Luis Obispo Co., CA.  Another example is shown for a specimen photographed by Chris Parish at Pt. Lobos State Park, Sea Lion Pt.,

     The 'Haleoid' variant of Niebla testudinaria is characterized by having a medium-size thallus, generally from 3–7 cm, much divided into relatively narrow prismatic branches. Two specimens collected by Charis Bratt, one from the Santa Ynez Mts., the other from Santa Cruz Is, are remarkably similar for their occurrence at disjunct locations. Their sublinear branches are similar to those of N. halei, which differs by the relatively small thallus (<3 cm diam.) that is more intricately divided into numerous capillary branches; it is known only from San Bruno Mt.  These differences suggest an evolutionary trend from erect sexual thalli (apothecia usually present) with occasional  isodichotomous branching—as seen in N. testudinaria typeto more increasingly branched asexual thalli (reproducing by branch fragmentation) as exhibited by the intermediate 'Haleiod' variant lacking apothecial development, and to the relatively small intricately divided thalli of N. halei.  A parallel trend is also evident within a putative sekikaic acid lineage in the Channel Islands, represented by N. siphonoloba in having mostly simple to occasionally divided branches, to more frequent branching in N. dissecta, and  to increasingly intricate branching towards the thallus apex as seen in N. dactylifera.  Generally, the cortical features of these sekikaic acid species appear more similar to each other than to the divaricatic acid species, although cortical features in a sekikaic-acid species are also more variable than observed for divaricatic-acid species, and some 'variants' are difficult to distinguish from divaricatic-acid species as discussed below under N. dissecta.  Other  much-branched thalli such as N. ramosissima (San Nicholas Is., divaricatic acid) and N. palmeri (northern Baja California, sekikaic acid) appear more related to N. disrupta than to N. siphonoloba, or to N. homalea than to N. testudinaria

       Niebla flagelliforma, a Baja California species, has similar reticulate ridging and branching to the 'Haleoid' variant but differs in having a thinner cortex on the upper branches—referred to as flagelliform branches, generally less than 35 µm thick, compared to 75–150 µm thick in the ultimate, often bifurcate, branchlets of N. testudinaria.  The thinner cortex is evident by the cortical ridges becoming more sharply raised in the upper branchlets. The terminal (flagelliform) branches of N. flagelliforma suggest an adaptation to growing in the warmer desert region of Baja California where often found away from the immediate coast on rocks surrounded by brush.   Conversely, the species with a thicker cortex, such as N. testudinaria and N. homalea, are better adapted to the cooler windy peninsulas along the California coast; their thicker cortex is like putting on a jacket for the cold fog, especially N. homalea with its extra coat of gloss.

     The 'Haleoid' variant of N. testudinaria is also similar to Niebla dissecta, distinguished in part by the presence of sekikaic acid as just indicated. Indeed, they (N. testudinaria, N. dissecta) can be difficult to separate morphologically because of their similar reticulate ribbing.  Nevertheless, N. dissecta generally differs by its basal branches that gradually ascend upwards and divide at wider angles in contrast to more erect branches of N. testudinaria, and while N. dissecta also differs by the more abundant terminal dactyliform branchlets, in contrast to the somewhat flattened bifurcate branchlets of N. testudinaria, hybrids also seem apparent.  These are not just different chemotypes of a species as some seem to suggest by stating that, for example, Niebla dissecta = N. homalea  (Björk, Ways of Enlichment lichen photogallery, website) when in fact they are not equal.  It must be recognized that DNA studies have yet to be published that disprove Spjut's (1996) species interpretation of Niebla, or support Bowler's super polymorphic species of Niebla, in which he also includes Vermilacinia

     A  Dissectoid' variant on Isla Guadalupe appears to have hybrid features of N. dilatata and N. testudinaria. The branches are strongly flattened as in N. dilatata with lacerated margins as in N. lobulata with which it may occur.  It is interesting note that these same species also occur (together) on Isla San Martín.

      A variant of  N. disrupta not shown above (Fig. 8.4 in Spjut 1996) is similar to  N. testudinaria in cortical ridging but differs in having sekikaic acid and whip-like branches.  The epithet disrupta given by Nylander suggests he may have recognized this species (N. disrupta) by the apothecium development that causes the growth of a branch to curve or change direction, sometimes nearly at right angles.   The mature apothecia of N. disrupta are usually found more in the lower to mid region of the thallus, in contrast to mature apothecia in N. homalea developing near the apex of the thallus.  In N. testudinaria apothecia are less frequently seen. This seems related to the more frequent bifurcate branching near apex. As with N. dissecta, N. disrupta differs from N. testudinaria in having sekikaic acid.  In further contrast is N. sorocarpia that has aggregate apothecia on fringed narrow to lobulate branchlets, which develop along the upper expanded portion of main branches; it occurs at Granite Pt. in Pt. Lobos State Park, judging from other images of Niebla on the web and from a specimen collected by Weber at Colorado.

     The homaleoid variant of Niebla testudinaria is similar to N. homalea by the more frequent twisting of branches and development of transverse cracks in the cortex. It also shows reticulate ridging and ±equally divided branches characteristic of N. testudinaria.  As already indicated, Niebla homalea generally differs by its unequal (anisodichotomous) division of branches, and by the branch appearing  more elliptical than prismatic in cross section.   The temptation is to include the 'Homaleoid' variant under N. homalea; however, this would weaken the taxonomic value of the reticulate ridging character for defining N. testudinaria. Alternatively, one might employ a suite of character traits, favoring N. testudinaria in some instances, and N. homalea in others.  In diploid plants, one might view this variation as a product of hybridization and introgression. But since the lichen thallus is largely somatic haploid mycelia, other symbiotic factors may be involved. For now, N. testudinaria is viewed as polymorphic in which some variants such as "Haleoid' may represent distinct species, others such as the 'Caespitoid' are seen as variation of the typical form, and those such as 'Homaleoid,' 'Disruptoid' (Morro Bay),  and 'Dissectoid' (Isla Guadalupe) are perhaps 'hybrids.'

         Additionally, Spjut and Marin, during 1985—in collecting 25 g samples of Niebla in Baja California for the NCI anti-HIV screening program—were able to obtain >95%  pure N. flagelliforma, N. eburnea, Vermilacinia laevigata, and N. podetiaforma at a time before these species were not known.  But they also encountered problems in obtaining pure N. caespitosa in that a sample assigned to this species under the name of Niebla sp. was later found to include  N. flabellata and V. ligulata—after further study and sorting with the aid of TLC. In 1986, they also had problems in the field in separating N. infundibula from N. homaleoides and N. josecuervoi on a ridge north of Punta Santa Rosarito while collecting for Dean Cassady's medicinal plant screening projects at Ohio State University, who was also a participant of our 1986 Baja expedition; three separate samples of these species required further sorting in the lab using TLC as a guide.  Thus, where it may be difficult to distinguish N. testudinaria, N. dissecta, and other related species by morphological characters, determination of the secondary lichen metabolites is necessary.


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Bowler, P. A. and J. Marsh.  2004. Niebla.  Lichen Flora of the Greater Sonoran Desert 2: 368–380. 

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DePriest, P. T. 1994. Variation in the Cladonia chlorophaea Complex II: Ribosomal DNA variation in a Southern Appalachian population. The Bryologist 97: 117–126.

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Spjut, R. W. 1995. Vermilacinia (Ramalinaceae, Lecanorales), a new genus of lichens. Pp. 337-351 in Flechten Follmann; Contr. Lichen. in honor of Gerhard Follmann, F. J. A. Daniels, M. Schulz & J. Peine, eds., Koeltz Scientific Books, Koenigstein.

_________. 1996. Niebla and Vermilacinia (Ramalinaceae) from California and Baja California. Sida, Botanical Miscellany 14: 1–207, 11 plates.


Additional References: See Niebla