Erysiphe ornata (Braun) Braun & Takamatsu, 2000
Betula pendula, Belgium, prov. Antwerp, Meerhout © Carina Van Steenwinkel
cleistothecium with appendages
Betula pendula, Belgium, prov. Antwerp, Mol, Buitengoor-Meergoor © Carina Van Steenwinkel: at left infection by Erysiphe ornata, at right by Phyllactinia betulae
same leaves, underside
the Phyllactinia cleistothecia are much larger. Contrary to Erysiphe, the mycelium of Phylactinia is partly internal, killing deeper cell layers, which locally results in a pale colour of the leaf.
mycelium evanescent, amphigenous. Appressoria lobed or multilobed, mostly single. Conidia solitary, oblong-elliptic, without fibrosin bodies. Cleistothecia with 3-6 asci, that contain 6-8 spores. Appendages 4-10, equatorial, 0.5-1 x the diameter; they are stiff, mostly rough, brown near the base, at the tip 4-6 x times in quick succession dichotomously branched; no, or just one, sept.
Betula humilis, nana, pendula, pubescens.
Microsphaera betulae Magnus, 1898; M. ornata Braun, 1982.
In Europe the variety europaea (Braun) Braun & Takamatsu, 2000. The typical form has a higher number of appendages (6-22) that moreover are longer (1-1.5 x the diameter of the cleistothecium). This form has been found in the Ukraine, and is also mentioned by Leysen from Belgium.
Adamska (2005a), Brandenburger (1985a: 53), Braun (1995a), Braun & Cook (2012a), Bresinsky (2016a), Czerniawska, Madej, Adamska ao (2000a), Dietrich (2016b), Dynowska, Fiedorowicz & Kubiak (1999a), Jage, Klenke & Kummer (2010a), Jage, Kruse, Kummer ao (2013a), Klenke & Scholler (1995a), Kruse (2014a, 2019a), Leysen (2017a), Mieslerová, Sedlářová, Michutová, ao (2020b), Talgø, Sundheim, Gjærum ao (2010a).