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Thelotrema lepadinum (Ach.) Ach.

Synonyms:

Family: THELOTREMATACEAE

Habitat: Oceanic zone

Description

    Thallus crustose, more or less thick depending upon the bark substratum, smooth to felt-like or slightly rugose, whitish, cream, cream-greenish. Apothecia usually numerous, evenly distributed, at the top of prominent warts, volcano-like with a base of 1-2 mm diam., and a summit open like a crater of 0.2-0.5 mm diam., rim irregular, with at the crater bottom a white-cream membrane, torn at maturity, leaving small white fragments aside and clearly visible at the center a brown, brown-ochraceous disc. Ascii 120-140 x 30-40 µm according to our measurements, (1) 2-3-4 (8)-septed. Ascospores colourless, remaining colourless until maturity, lenghtly fusiform, with 10-18 transverse and 1-5 longitudinal septa (aspect of grid or corn cob section or intestine in optical section), 60-140 x 12-28 µm according to literature, 70-125 x 15-30 µm according to our measurements. Photobiont : Trentepohlia. Chemical spot tests negative, although some specimens are sometimes K+ yellow turning to orange-red. Strong oceanic trends, on bark of trees in humid oceanic woodlands, seldom on mossy and humid rocks of oceanic woodlands (see Thelotrema lepadinum rock form). N.B. According to the properties of the bark surface, smooth or rough, this species may show a variable appearance, notably concerning the look and distribution of apothecia, see for exemple Thelotrema lepadinum forma on Ilex bark, whose thallus is grey blueish and of which apothecia are more scaterred and less proeminent. Not to be confused with Pertusaria hymenea et Pertusaria leioplaca of which the apothecia and ascospores have a different structure.*







Thelotrema lepadinum Cranou 1
Bernard BOUFFINIER



Thelotrema lepadinum Cranou 2
Alain GERAULT



Thelotrema lepadinum Cranou 3
Joƫl QUERELLOU



Thelotrema lepadinum Cranou 4
Alain GERAULT



Thelotrema lepadinum Cranou 5
Joƫl QUERELLOU



Thelotrema lepadinum Cranou 6
Joƫl QUERELLOU



Thelotrema lepadinum Cranou 7
Joƫl QUERELLOU



Thelotrema lepadinum Cranou 8
Bernard BOUFFINIER



Thelotrema lepadinum Belgique Couvin 1
Jacques HAINE



Thelotrema lepadinum Belgique Couvin 2
Jacques HAINE



Thelotrema lepadinum Coupe apothƩcie Bleu Coton diluƩ Belgique Couvin 3
Jacques HAINE



Thelotrema lepadinum Asques eau Belgique Couvin 4
Jacques HAINE



Thelotrema lepadinum Asque Bleu Coton Belgique Couvin 5
Jacques HAINE



Thelotrema lepadinum Asque Bleu Coton diluƩ Belgique Couvin 6
Jacques HAINE



Thelotrema lepadinum Spore Bleu Coton Belgique Couvin 7
Jacques HAINE



Thelotrema lepadinum Spores Bleu Coton Belgique Couvin 8
Jacques HAINE



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