Aecidium ranunculi-acris Persoon, 1800
on Ranunculus
Ranunculus acris, Belgium, prov. Namur, Couvin, Aublain © Sébastien Carbonnelle; also the petioles and stems may be galled.
Ranunculus repens, Flevoland, Reve-Abbertbos © Hans Jonkman
detail; the tiny orange spots are the spermogonia
underside of the gall, with the aecia

Ranunculus repens, Voorne’s Duin © Ben van As

underside of the leaf, with aecia
gall
aecia yellow, hypophyllous, on yellowed and galled spots.
host plants
Ranunculaceae, monophagous
Ranunculus aconitifolous, acris, alpestris, arvensis, auricomus, breyninus, bulbosus, lanuginosus, lingua, montanus, parnassifolius, platanifolius, polyanthemos & subsp. nemorosus, repens, sceleratus.
notes
check here about the the genus Aecidium.
references
Jage, Scholler & Klenke (2010a), Klenke & Scholler (2015a), Kruse (2014a, 2019a), Kummer (2012a).