Dichotomous table for gallers on Oxytropis
by Hans Roskam
1a On above ground organs => 2
1b Oval to cylindrical nodules, terminally sometimes hand-shaped or forked, coralloid. Oxytropis spp.: Rhizobium leguminosarum
2a On stems, leaf axis or shoot tips => 5
2b On leaflets => 3
3a Galls caused by animals => 4
3b Large parts of plants slightly disfigured and etiolated by a perennial mycelium. Aecia usually often many on the undersides of many leaves, distinguished by their pale colour. O. campestris & subspp. sordida + tyroliensis, jacquinii: Uromyces lapponicus
4a Halves of leaf blade folded together, slightly thickened. Containing one or two at first yellowish larvae. O. jacquinii – Unidentified gall midge
4b Halves of leaf blade folded upwards, pod-like, distinctly thickened. O. campestris: Unidentified gall midge
5a Whole plant stunted. Shoot tip and side shoots transformed into a mass of strongly felt-like pubescent leaflets. Shoot axis ± bent. Larvae pale yellow. O. pilosa: Unidentified gall midge
5b Shoot axis, petiole and midrib (rarely also midrib of a leaflet), with single or several, mainly one-sided, 2–5 mm long, tough, one-chambered, often yellowish swellings; occasionally coalescing on stem into multi-chambered galls. O. pilosa: ? gall midge, ? chalcid