Melanustilospora ari (Cooke) Denchev, 2003
on Arum, Biarum
Arum maculatum, Belgium, prov Liège, Kelmis, vallée de la Gueule en amont de Plombières, 17.iv.2022 © Carina Van Steenwinkel
same leaf seen from above, from below, and lighted from behind.
also in the petiole
spore mass in the mesenchym
spores (without the gelatinous mantle) 11-15 x 12-19 µm.
Relatively extensive, ill-delimited, greyish green leaf spots, not delimited by veins. The infection is inconspicuous, the leaf surface is only lightly swollen. Embedded in the leaf tissue lie masses of roundish, yellow-brown spores with a smooth, double wall of uneven thickness, 13-17 µm in diameter.
Plants with blackish swollen spots like in the pictures below, have nothing to do with the fungus and are not pathological at all (verified by Carina).
Arum maculatum, Belgium, prov. Namur, Lavaux-Sainte-Anne © Chris Snyers
Almaraz (1998a), Buhr (1964b), Denchev (2003a), Klenke & Scholler (2015a), Kruse (2019a), Lotze-Engelhard (2010a), Mayor (1975a), Redfern & Shirley (2011a), Savchenko, Dzyunenko & Heluta (2010a), Savchenko & Heluta (2012a), Scholz & Scholz (2013a), Van Steenwinkel, Fraiture & Vanderweyen (2022b), Tomasi (2014a), Tóth (1994a), Vánky (1994a, 2012a), Vánky, Lutz & Bauer (2008b).