Urocystis johansonii (Lagerheim) Magnus, 1896
on Juncus
gall
the basal part of the lower leaves is swollen into a lead-coloured globule; when this ruptures a powdery black mass of spore balls is released.
hostplants
Juncaeae, narrowly monophagous
Juncus bufonius, pygmaeus.
references
Almaraz (1998a), Buhr (1964b), Klenke & Scholler (2015a), Tomasi (2014a), Vánky (1994a).