Dichotomous table for gallers on Petroselinum crispum
by Hans Roskam
1a On parts of flowering- or fruiting inflorescences => 6
1b On stems and leaves => 2
2a Expanded malformations of variable shape => 4
2b Oval or spindle-shaped galls on stems, petioles or leaf veins => 3
3a Small galls on root collar or stem base or leaves of young plants, basally distinctly broadened and swollen. Containing a single larva. Calosirus terminatus
3b Spindle-shaped, sometimes coalescing, usually only weak and slightly expanded bulges on petioles, midrib, main veins and young stems. Puccinia nitida
4a Malformations mainly of leaf blades => 5
4b Petioles, midrib, sometimes also the basal parts of leaflets of severely stunted young plants are variously disfigured, swollen and spongy. Ditylenchus dipsaci
5a Leaf midrib ± shortened and curved, with clustered, curled, deflected leaflets. Philaenus spumarius
5b The tips of leaflets, usually of many severely stunted and disfigured leaves, are deflected and sometimes swollen and tuberculate. Trioza apicalis
5c Malformation caused by aphid. Upper leaves curled, lower leaves atrophied; leaf blade sometimes arched downwards and curled on upperside. Hyadaphis foeniculi
6a Centre of umbel or stalk of umbel ± swollen, club-shaped. Inner wall covered with mycelium. Containing a red larva. Lasioptera carophila
6b Fruit strongly inflated, bladder-like; galls ± reddened, protruding above the umbel; containing a single orange-red larva. Kiefferia pericarpiicola