Dichotomous table for gallers on Oxalis
by Hans Roskam
1a On parts above ground => 2
1b Roots with nodular swellings. O. stricta: Meloidogyne hapla
2a On vegetative organs => 4
2b On flowers and fruits => 3
3a Flowers greened, ovaries elongated. O. acetosella, articulata, corniculata, stricta: Aceria oxalidis
3b Anthers and ovaries slightly swollen, later on containing reddish-brown spores. Diseased capsules sterile. Infestation not distinct before dusting of spores. O. fontana, stricta; not on O. corniculata: Thecaphora oxalidis
4a Malformations extended over several organs => 6
4b Galls localised => 5
5a Less than 1 mm long, sometimes joined, yellow many-celled warts on basal leaf- and stem parts. O. stricta: Synchytrium aureum
5b Slightly thickened cushions on leaves and petioles, with distinctly arched, cup-shaped aecia. ~, in NW-Eu on O. corniculata, fontana, stricta: Puccinia sorghi
6a Leaflets stunted, shorter stalked. Leaf blade rolled inwards, ± folded and twisted, finely wrinkled. O. acetosella, articulata, corniculata, stricta: Aceria oxalidis
6b Plant stunted, variously disfigured. Oxalis spp.: Aphis fabae