Hypotrachyna horrescens (Taylor) Krog & Swinscow

Lichenologist, 19: 420, 1987. Basionym: Parmelia horrescens Taylor in Mackay - Fl. Hibern., 2: 144, 1836.
Synonyms: Parmelia dissecta Nyl.; Parmelina dissecta (Nyl.) Hale; Parmelina horrescens (Taylor) Hale; Parmelinopsis horrescens (Taylor) Elix & Hale
Distribution: N - Lig (Giordani & Brunialti 2000, Brunialti & Giordani 2003, Watson 2014). C - Tosc (FI 315), Laz (Ravera 2008), Sar.
Description: Thallus foliose, heteromerous, dorsiventral, rather loosely attached, forming 2-5(-7) cm wide, irregular rosettes, isidiate. Lobes narrow, 0.2-3 mm wide, irregularly branched with rounded axils, contiguous and often imbricate, with truncate to subrotund apices, the margins indented and often lacinate, apparently with simple, black up to 0.8 mm long marginal cilia (actually projecting rhizines). Upper surface whitish grey to greenish grey, smooth, shiny, epruinose, usually emaculate, densely covered in cylindrical to lobulate-coralloid, apically often brownish, short-ciliate isidia, the cilia black, 0.1-0.4 mm long. Lower surface black, shiny, densely rhizinate, with a narrow, naked, brown marginal zone; rhizines black, shiny, simple to rarely dichotomously branched, usually projecting beyond lobe margins. Upper cortex of tightly packed, anticlinally oriented hyphae, with a pored epicortex, the cell walls with isolichenan; medulla white; algal layer continuous; lower cortex brown, of anticlinally oriented hyphae. Apothecia very rare, lecanorine, laminal, to 5 mm across, with a brown disc and an isidiate thalline margin. Asci 8-spored, clavate, Lecanora-type. Epithecium brown; hymenium and hypothecium colourless. Ascospores 1-celled, hyaline, broadly ellipsoid, (12-)15-19 x 7-10(-12) µm. Pycnidia rare, immersed. Conidia cylindrical, 3-5 x c. 0.5 µm. Photobiont chlorococcoid. Spot tests: upper cortex K+ yellow, C-, KC-, P-; medulla K-, C-, KC+ pink, P-. Chemistry: upper cortex with atranorin and chloroatranorin; medulla with gyrophoric acid (major), lecanoric and umbilicaric acids (minor), and related accessory substances (hiascic, 4,5-di-0-methylhiascic, 4-0-methylhiascic acids).
Note: a mild-temperate to humid subtropical lichen found on old trees in ancient, open, humid forests. According to Masson (2005) this is an Atlantic species: at least the records from the Alps and from the Adriatic part of the Peninsula should correspond to H. minarum. I still leave under this name the records from Tyrrhenian Italy, where several subatlantic species do occur: in any case, the Italian material badly needs revision, and the presence of this species in Italy is dubious. The species is included in the Italian red list of epiphytic lichens as “Near-threatened” (Nascimbene & al. 2013c).
Growth form: Foliose, broad lobed
Substrata: bark
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly asexual, by isidia, or isidia-like structures (e.g. schizidia)
Most common in areas with a humid-warm climate (e.g. most of Tyrrenian Italy)

Commonnes-rarity: (info)

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

pH of the substrata:

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Solar irradiation:

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Aridity:

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Eutrophication:

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Poleotolerance:

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Altitudinal distribution:

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Predictive model
Herbarium samples


Felix Schumm – CC BY-SA 4.0
Image from: F. Schumm (2008) - Flechten Madeiras, der Kanaren und Azoren. Beck, OHG - ISBN: 978-3-00-023700-3



G. Incerti; Owner: Department of Life Sciences, University of Trieste
Herbarium: TSB (21803)
2001/11/26


Harry Taylor; Owner: Natural History Museum London
Ramk)


Harry Taylor; Owner: Natural History Museum London
Ramk)


Andreé Aptroot; Owner: André Aptroot - Source: http://www.tropicallichens.net/ - Licence: CC BY-SA-NC
Taiwan


Laurens Sparrius; Owner: Laurens Sparrius - Source: http://www.tropicallichens.net/ - Licence: CC BY-SA-NC
Taiwan



Felix Schumm - CC BY-SA 4.0
[9205], Spanien, Kanarische Inseln, La Gomera, zwischen Arure und Vallehermoso südlich Chorros de Epina. Im Lorbeer-Erica Wald. 28°09.593’ N, 17°18.117’ W, 1020 m. Leg. Schumm 10.02.2002, det. Elix 22.11.2002.



Felix Schumm - CC BY-SA 4.0
[9205], Spanien, Kanarische Inseln, La Gomera, zwischen Arure und Vallehermoso südlich Chorros de Epina. Im Lorbeer-Erica Wald. 28°09.593’ N, 17°18.117’ W, 1020 m. Leg. Schumm 10.02.2002, det. Elix 22.11.2002.



Felix Schumm - CC BY-SA 4.0
[9205], Spanien, Kanarische Inseln, La Gomera, zwischen Arure und Vallehermoso südlich Chorros de Epina. Im Lorbeer-Erica Wald. 28°09.593’ N, 17°18.117’ W, 1020 m. Leg. Schumm 10.02.2002, det. Elix 22.11.2002.



Felix Schumm - CC BY-SA 4.0
[9205], Spanien, Kanarische Inseln, La Gomera, zwischen Arure und Vallehermoso südlich Chorros de Epina. Im Lorbeer-Erica Wald. 28°09.593’ N, 17°18.117’ W, 1020 m. Leg. Schumm 10.02.2002, det. Elix 22.11.2002.



Felix Schumm - CC BY-SA 4.0
[9205], Spanien, Kanarische Inseln, La Gomera, zwischen Arure und Vallehermoso südlich Chorros de Epina. Im Lorbeer-Erica Wald. 28°09.593’ N, 17°18.117’ W, 1020 m. Leg. Schumm 10.02.2002, det. Elix 22.11.2002.



Felix Schumm - CC BY-SA 4.0
[9205], Spanien, Kanarische Inseln, La Gomera, zwischen Arure und Vallehermoso südlich Chorros de Epina. Im Lorbeer-Erica Wald. 28°09.593’ N, 17°18.117’ W, 1020 m. Leg. Schumm 10.02.2002, det. Elix 22.11.2002.



Felix Schumm - CC BY-SA 4.0
[9205], Spanien, Kanarische Inseln, La Gomera, zwischen Arure und Vallehermoso südlich Chorros de Epina. Im Lorbeer-Erica Wald. 28°09.593’ N, 17°18.117’ W, 1020 m. Leg. Schumm 10.02.2002, det. Elix 22.11.2002.



Felix Schumm - CC BY-SA 4.0
[9205], Spanien, Kanarische Inseln, La Gomera, zwischen Arure und Vallehermoso südlich Chorros de Epina. Im Lorbeer-Erica Wald. 28°09.593’ N, 17°18.117’ W, 1020 m. Leg. Schumm 10.02.2002, det. Elix 22.11.2002.



Felix Schumm - CC BY-SA 4.0
[9205], Spanien, Kanarische Inseln, La Gomera, zwischen Arure und Vallehermoso südlich Chorros de Epina. Im Lorbeer-Erica Wald. 28°09.593’ N, 17°18.117’ W, 1020 m. Leg. Schumm 10.02.2002, det. Elix 22.11.2002.



Felix Schumm - CC BY-SA 4.0
[9205], Spanien, Kanarische Inseln, La Gomera, zwischen Arure und Vallehermoso südlich Chorros de Epina. Im Lorbeer-Erica Wald. 28°09.593’ N, 17°18.117’ W, 1020 m. Leg. Schumm 10.02.2002, det. Elix 22.11.2002.



Felix Schumm - CC BY-SA 4.0
[9205], Spanien, Kanarische Inseln, La Gomera, zwischen Arure und Vallehermoso südlich Chorros de Epina. Im Lorbeer-Erica Wald. 28°09.593’ N, 17°18.117’ W, 1020 m. Leg. Schumm 10.02.2002, det. Elix 22.11.2002.



Felix Schumm - CC BY-SA 4.0
[9205], Spanien, Kanarische Inseln, La Gomera, zwischen Arure und Vallehermoso südlich Chorros de Epina. Im Lorbeer-Erica Wald. 28°09.593’ N, 17°18.117’ W, 1020 m. Leg. Schumm 10.02.2002, det. Elix 22.11.2002.



Felix Schumm - CC BY-SA 4.0
[9205], Spanien, Kanarische Inseln, La Gomera, zwischen Arure und Vallehermoso südlich Chorros de Epina. Im Lorbeer-Erica Wald. 28°09.593’ N, 17°18.117’ W, 1020 m. Leg. Schumm 10.02.2002, det. Elix 22.11.2002.



Felix Schumm - CC BY-SA 4.0
[9205], Spanien, Kanarische Inseln, La Gomera, zwischen Arure und Vallehermoso südlich Chorros de Epina. Im Lorbeer-Erica Wald. 28°09.593’ N, 17°18.117’ W, 1020 m. Leg. Schumm 10.02.2002, det. Elix 22.11.2002.