Sticta fuliginosa ss. str.
Thallus foliose, 5-10 cm diam., composed of several lobes, sometimes more or less branched, ascending, more or less overlapping, lobes round or suborbicular, without pseudostipe, papyraceous when moist and rather breakable when dry, margin regular to wavy, entire to crenulate or lacerate. Upper surface smooth to somewhat scrobiculate or minutely furrowed, macula and cilia absent, grey to grey-brownish when dry, brownish when moist, covered with isidia, 0.5 mm tall, especially abundant towards the apices of furrows, sometimes clustered in coralloid minute mounds, darker than the thallus. Lower surface more or less scrobiculate, cream to pale brownish, darker towards the center, faintly pubscent, sometimes hirsute in some sections, cyphellae numerous mostly towards the margin, rounded to angular, cup-shaped to urceolate with a margin sometimes slightly prominent, 0.5-2 mm diam., membrane without papillae visible (optical microscope required). Apothecia very rare, more or less sessile, 1-2.5 mm diam., disc flat at first then slightly convex, red-orange, brown-orange, exciple minutely ciliate, cilia short (100-200 x 4-5 µm), colourless, most of the cilia located below the disc surface. Ascii: 60-100 x 14-27 µm, with an enlarged and thickenned apex. Ascospores narrowly ellipsoid, one apex pointed, 1-3 (4-5)-septate with a small constriction at the septum level and quite often 2 secondary septa without similar constriction suggesting 3-septate ascospores, 30-35 x 7-11 (12) µm according to our measures. Photobiont: Nostoc. Chemical spot tests negative but production of fish smell when crushed. This species (ss. str.) ir rare in our region and is found mainly on mossy trunks of trees in very humid oceanic woodlands, notably near rivers and streams, seldom on mossy rocks. Sticta ciliata differs notably by its white cilia towards the lobe margins, its apothecia and its most frequent habitat: rocks. Sticta fuliginoides is more difficult to distinguish but its thallus is limited to a single lobe with a conspicuous revolute margin ( agaric-shaped in section).
For more details, refer to:
MAGAIN N., SERUSIAUX E. Mycol Progress (2015) 14:97. Dismantling the treasured flagship lichen Sticta fuliginosa (Peltigerales) into four species in Western Europe. Download : http://hdl.handle.net/2268/186416