Dichotomous table for gallers on Vincetoxicum hirundinaria
by Hans Roskam
1a On flowers or fruits => 4
1b On vegetative organs => 2
2a Leaf blades converging, distorted or curled => 3
2b Leaf margin narrowly rolled upwards, more rarely downwards, discoloured.
Unidentified gall mite
3a Young axis locally stunted; several leaves clustered, converging, ± nest-like. Leaf blades curled, deep green close to the froth-covered nymph. Philaenus spumarius
3b Leaf blades slightly clustered, curved and distorted. Inducer unknown – ? insect
4a On fruits; malformations facultative, usually minor => 5
4b Flower buds enlarged, cartilaginously thickened; ± reddish; later on rupturing, with thick, short lobes. Containing white to yellowish, jumping larva. Contarinia vincetoxici
5a Fruit slightly swollen; often hardly changed, sometimes ± wrinkled and discoloured. Containing several slender, white, jumping larvae. Contarinia asclepiadis
5b Fruit swollen, sometimes curved, ± yellowish, reddish or violet. Containing many cylindrical larvae. Euphranta connexa