Filipendula ulmaria, Vlaardingen, Holy-natuurpark © Ben van As

gall

mycelium amphigenous, also on stems, white, persistent; infected stems often distorted. Appressoria indistinct. Conidia oval, formed in chains, with fibrosin bodies. Cleistothecia, often in groups, with a single ascus, containing 6-8 spores. Appendages numerous, ± equatorial, 1-5 x the diameter; they are ± stiff, curved, septate, simple, dark brown when mature.

host plants

Rosaceae, monophagous

Filipendula kamtschatica, ulmaria, vulgaris.

notes

morphologically, the fungus cannot be distinguished from Podosphaera spiraeae, and on this ground it has long been considered synonymous with that species. However, DNA research has demonstrated that two perfectly separated species are involved.

references

Braun & Cook (2012a), Bresinsky (2016a), Doppelbaur & Doppelbaur (1973a “Sphaerotheca macularis”), Klenke & Scholler (2015a), Kruse (2014a, 2019a), Leysen (2017a), Scholler, Reinhard & Schubert (1996a [Sphaerotheca spinaeae on Filipendula ulmaria]).