Cetraria muricata (Ach.) Eckfeldt

Bull. Torrey Bot. Club, 22: 240, 1895. Basionym: Lichen muricatus Ach. - Lichenogr. Suec. Prodr.: 214, 1799.
Synonyms: Cetraria aculeata f. hispida Cromb.; Cetraria aculeata var. alpina Schaer.; Cetraria stuppea (Flot.) Zopf; Coelocaulon aculeatum subsp. hispidum (Cromb.) D. Hawksw.; Coelocaulon muricatum (Ach.) J.R. Laundon; Cornicularia aculeata var. alpina (Schaer.) Rabenh.; Cornicularia aculeata var. muricata (Ach.) Ach.; Cornicularia muricata (Ach.) Ach.; Cornicularia tenuissima var. hispida (Cromb.) Keissl.; Cornicularia tenuissima var. muricata (Ach.) Dalla Torre & Sarnth.
Distribution: N - Frl (Tretiach & Hafellner 2000), Ven (Nascimbene & Caniglia 2000), TAA (Bilovitz & al. 2014, 2014b), Lomb (Gheza 2017), Piem (Matteucci & al. 2015b), VA (Piervittori & Isocrono 1997, 1999, Piervittori & al. 2004, Isocrono & al. 2008, Matteucci & al. 2015c), Emil (Fariselli & al. 2020), Lig (Jatta 1909-1911). C - Tosc (Benesperi & Lastrucci 2007, Giordani & al. 2009, Lastrucci & al. 2009), Abr (Ravera 2002b, Gheza & al. 2021), Sar. S - Camp, Bas (Potenza & Fascetti 2005, 2012, Potenza 2006), Cal (Puntillo 1996, Potenza & al. 2011), Si (Ottonello & Romano 1997, Brackel 2008b, Ottonello & al. 2011).
Description: Thallus fruticose, richly dichotomously branched, forming dense, shrubby, loosely attached tufts, matt to glossy brown or almost black, fragile. Branches more or less terete, not dorsiventral, usually rather smooth and even, delicate 1-3(-5) cm tall, spinulose, the main ones 0.3-0.5 mm thick; pseudocyphellae punctiform, flat to slightly depressed, more or less circular, often poorly visible. Cortex three-layered, with a denser, brown outer layer with accumulation of dead cells, an intermediate layer with hyphae more or less sparsely distributed in a gelatinous matrix, and a colourless inner layer with more conglutinated cells; medulla white, lax but usually solid also in basal parts. Apothecia rare (not seen in Italian material), lecanorine, sessile, up to 8 mm across. Epithecium brown; hymenium colourless, 35-50 μm high, I+ blue; paraphyses coherent, the apical cells slightly swollen; hypothecium colourless, underlain by a dense algal layer. Asci 8-spored, Lecanora-type. Ascospores 1-celled, hyaline, ellipsoid, 5.5-6.5 x 2.5-3.5 μm. Pycnidia dark, terminal or immersed in the spinulose projections. Conidia fusiform, 5-6 x 1-1.5 μm. Photobiont chlorococcoid. Spot tests: cortex and medulla K-, C-, KC-, P-. Chemistry: medulla with lichesterinic and protolichesterinic acids.
Note: optimum on siliceous soil in wind-exposed siliceous ridges above treeline, but also found on decalcified soils on calcareous substrata. The distinction from C. aculeata is not always clear to me: especially in southern Italy there are specimens which are difficult to assign to either taxon.
Growth form: Fruticose

Substrata: soil, terricolous mosses, and plant debris
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly sexual

Commonnes-rarity: (info)

Alpine belt: rather rare
Subalpine belt: rather common
Oromediterranean belt: rare
Montane belt: very rare
Submediterranean belt: extremely rare
Padanian area: absent
Humid submediterranean belt: extremely rare
Humid mediterranean belt: absent
Dry mediterranean belt: absent

pH of the substrata:


Solar irradiation:








Altitudinal distribution:


Predictive model
Herbarium samples

Einar Timdal - Source: http://nhm2.uio.no/lav/web/index.html - CC BY-NC

P.L. Nimis; Owner: Department of Life Sciences, University of Trieste
Herbarium: TSB (2546)

P.L. Nimis; Owner: Department of Life Sciences, University of Trieste
Herbarium: TSB (2546)
detail of pseudocyphellae

Andres Saag; Owner: University of Tartu

Triin Aimla; Owner: University of Tartu

Helena Rodriguez
Spain, Galicia, Peña Trevinca