Key to the species of S. subg. Palustres

1. Stem and synflorescence glabrous................................................................................................................................. S. sosnowskyi

– Upper part of stem and synflorescence glandular-eglandular hairy ................................................................................................... 2

2. Root tuberous; capitula with 40–50 florets; achenes without secondary ribs ............................................................. S. erzincanicus

3. Root short-thick woody rhizome; capitula with 70–90 florets; achenes with secondary ribs........................................... S. palustris