Dichotomous table for gallers on Conium maculatum
by Hans Roskam
1a On inflorescences or fruits => 5
1b On vegetative parts => 2
2a Malformations caused by animal parasites => 3
2b Bulge-shaped, sometimes distorted, about 10 mm long swellings on leaf veins, -midrib and -stalk, bearing cinnamon-brown uredinia, occasionally also on younger stem parts and even in inflorescence. Puccinia conii
3a Malformations caused by aphids => 4
3b Leaf blade over large parts nest-like downwards deflected; leaf tips slightly curled and deep-green. Philaenus spumarius
4a Axis of leaf tip conspicuously distorted and twisted; leaf blades folded and curled. Aphid about 2 mm long; pale green, with pale siphunculi, these much longer than cauda, which bears an appendage. Antennae shorter than half the body length. Cavariella pastinacae
4b Malformations similar. Aphid 1.5–2.4 mm, grey-green, often blackish-brown. Siphunculi very dark, about as long as cauda. Antennae ⅓–½ body length. Hyadaphis foeniculi
5a Stalk at centre of (partial) umbel ± globular to club-shaped swollen. Inner wall covered with mycelium. Containing a red larva. Lasioptera carophila
5b Fruit strongly swollen, globular to rotund-oval; galls protruding above the umbel; glabrous, ± reddened. Containing an orange-red larva. Kiefferia pericarpiicola
5c Inside disfigured fruits of C. maculatum develop uredinia of Puccinia conii