Trollius L.

Tutin, T. G., Heywood, V. H., Burges, N. A., Moore, D. M., Valentine, D. H., Walters, S. M. & Webb, D. A., 1964, Flora Europaea - Volume 1. Lycopodiaceae to Platanaceae, Cambridge University Press : 210

6. Trollius L. 1

Perennial herbs. Flowers with all parts spirally arranged. Perianth-segments 5-15, petaloid; honey-leaves 5-15, small, narrow, yellow. Stamens numerous. Fruit of many follicles. Perianth-segments strongly incurved; honey-leaves as long as stamens 1. europaeus

Perianth-segments not strongly incurved; honey-leaves 2-3 times as long as stamens 2. asiaticus