Xanthomendoza fallax (Hepp) Søchting, Kärnefelt & S.Y. Kondr.

Mitt. Inst. allg. Bot. Hamburg, 30-32: 237, 2002.. Basionym: Placodium fallax Hepp - Flecht. Eur., XI. no. 633. 1860.
Synonyms: Lecanora candelaria var. substellaris Ach.; Physcia controversa auct. ital. p.p. ; Physcia fallax Hepp ex Arnold nom. illegit. ; Xanthoria fallax Hepp ex Arnold; Xanthoria substellaris (Ach.) Vain.
Distribution: N - Frl (TSB 16119), Lomb (TSB 12761).
Description: Thallus foliose, heteromerous, dorsiventral, yellowish red to orange-brown, adnate to loosely adnate, lobed, forming regular to irregular, 1-2 cm wide rosettes which often coalesce to cover much larger surfaces. Lobes flattened, 2.5-5 mm long, the marginal ones 0.3-0.6 mm wide, smooth, with marginal soredia. Lower surface white to yellow, somewhat wrinkled, with white rhizines. Upper and lower cortex paraplectenchymatous; medulla white. Apothecia lecanorine, very rare, 0.5-0.7 mm across, laminal, stipitate, the margin initially smooth but often becoming sorediate. Thalline exciple paraplectenchymatous; proper exciple a strongly gelatinized plectenchyma with unoriented, short-celled hyphae; epithecium orange-brown, K+ purple-red; hymenium colourless; paraphyses simple or sparingly branched; hypothecium colourless. Asci 4-6-spored, clavate, functionally unitunicate, apically thickened with a broad internal beak, the inner part of apex and external cap I+ blue, Teloschistes-type. Ascospores 2-celled, polarilocular, hyaline, ellipsoid, (10.5-)12-16 x 6.5-8 µm, the equatorial thickening (“septum”) 3.5-5(-6) µm. Pycnidia common, immersed to projecting, darker orange than thallus. Conidia short-bacilliform. Spot tests: thallus and soredia K+ purple-red, C-, KC-, P-, UV+ orange. Chemistry: parietin (major), fallacinal (major), emodin, teloschistin (major) and parietinic acid (chemosyndrome A3 of Søchting 1997).
Note: this mainly northern to montane species mainly grows on siliceous or calcareous rocks. Almost all records of X. fallax from Italy are from bark and refer to the mainly epiphytic X. huculica (see note on that species).
Growth form: Foliose, narrow lobed
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly asexual, by soredia, or soredia-like structures (e.g. blastidia)
Subcontinental: restricted to areas with a dry-subcontinental climate (e.g. dry Alpine valleys, parts of Mediterranean Italy)

Commonnes-rarity: (info)

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

pH of the substrata:

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Solar irradiation:

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Eutrophication:

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Poleotolerance:

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Altitudinal distribution:

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Predictive model
Herbarium samples
INDEX FUNGORUM GBIF DOLICHENS

Jacques Haine - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=1040&lang=en
France, Drôme


Jacques Haine - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=1040&lang=en
France, Drôme


Jacques Haine - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=1040&lang=en
France, Drôme


Jacques Haine - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=1040&lang=en
France, Drôme


Jacques Haine - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=1040&lang=en
France, Drôme


Jacques Haine - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=1040&lang=en
France, Drôme


Jacques Haine - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=1040&lang=en
France, Drôme


Jacques Haine - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=1040&lang=en
France, Drôme


Jacques Haine - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=1040&lang=en
France, Drôme


Jacques Haine - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=1040&lang=en
France, Drôme


Jacques Haine - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=1040&lang=en
France, Drôme


Jacques Haine - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=1040&lang=en
France, Drôme


Source: Lindblom, L., Blom, H. H. & Timdal, E. 2019. The genus Xanthomendoza in Norway. Graphis Scripta 31 (7): 54–75. Oslo. ISSN 2002-4495 - CC BY-4.0
Xanthomendoza fallax. Field photograph of O-L-136166, Norway, Telemark, Skien. Scale bar: 2 mm. Photo: E. Timdal 2005-05-07


Wolfgang von Brackel - CC BY-4.0
Germany, Bavaria, Hohenfels


Wolfgang von Brackel - CC BY-4.0
Germany, Bavaria, Hohenfels


Wolfgang von Brackel - CC BY-4.0
Germany, Bavaria, Hohenfels


Wolfgang von Brackel - CC BY-4.0
Germany, Bavaria, Lauterachtal


Wolfgang von Brackel - CC BY-4.0
Germany, Bavaria, Lauterachtal