Plant Parasites of Europe

leafminers, galls and fungi

gallers on Helleborus

Dichotomous table for gallers on Helleborus

by Hans Roskam

1a Malformations caused by fungi with erupting or clearly transparent sori => 4

1b Malformations caused by animal inducers or fungi with fruiting bodies which are not apparent externally => 2

2a Pustule-shaped or minor bulge-like swellings on stems and leaves => 3

2b Leaf blades ± twisted, with margins downwardly deflected. H. foetidus, lividus & subsp. corsicus, niger, orientalis, purpurascens, viridis & subsp. bocconei: Macrosiphum hellebori

3a Leaf blade, more rarely petiole, with pustule-like necrotic oval swellings, up to 3 mm long, visible on both sides or on underside only; usually in two rows along the midrib. Each pustule containing a greenish-white egg; after emerging the larva lives freely on the leaf blade. “Procecidium” (oviposition scar, not a true gall). H. foetidus, niger, viridis: Monophadnus latus

3b Weak, at first ± vitreous, spindle-shaped swellings on stems and petioles. H. viridis: Physoderma deformans

4a Galls caused by rusts and smuts => 5

4b Galls caused by false mildew. Systemic infection of overwintering mycelium in rhizome. The diseased leaves are smaller, yellowish, the segments ± distinctly spoon-shaped downwardly deflected and curved; soon covered by a widespread, dense layer of conidia. H. dumetorum, foetidus, niger, odorus, purpurascens, viridis & subsp. istriacus: Peronospora pulveracea

5a Initially grey translucent smut bulges of variable size on all green parts, soon erupting and with black dusting. Helleborus spp.: Urocystis floccosa

5b Yellow aecia pads associated with spermogonia on gall-like swollen, sometimes ± bent petioles and leaf blades. Helleborus spp.: Puccinia actaeae-elymi

5c In similar aecia. Helleborus spp.: Puccinia actaeae-agropyri

Last modified 14.v.2020