Dichotomous table for gallers on Matthiola
by Hans Roskam
1a On parts above ground => 2
1b Roots with ± expanded, spindle-shaped to cylindrical, compact swellings. M. longipetala subsp. bicornis, tricuspidata: Plasmodiophora brassicae
2a Galls of irregular shape are expanded to involve several organs or larger parts of single organs => 3
2b White bulges, up to about 10 mm long, at first glossy, porcelain-like, later on dusty on axial parts of leaves or on stems. M. fruticulosa, incana: Albugo candida
3a Malformations caused by animals => 4
3b Stems or leaf axis diseased and swollen over different lengths, sometimes curved and soon covered by a down of white conidiophores. M. incana: Peronospora matthiolae
4a One-sided infected axis ± curved, leaves clustered, deflected over their tip and slightly curled. M. incana: Philaenus spumarius
4b Locally restricted or extensive on young leaves, ± discoloured folds and curls of the leaf blade. M. incana: Brevicoryne brassicae