Plants usually woody and climbing; leaves opposite or rarely absent 13. Clematis

Plants usually herbaceous and usually not climbing; leaves alternate or all basal, sometimes with a whorl of bracts below the flowers which can be mistaken for leaves 2.

Fruit of one or more follicles 3.

Fruit a group of achenes or berry-like 12.

Flowers bilaterally symmetric 4.

Flowers radially symmetric 6.

Ovary of one carpel; follicle one 7. Consolida

Ovary of 2 or more carpels; follicles 2 or more 5.

Upper perianth segments hooded or helmet-like 6. Aconitum

Upper perianth segments with a spur 8. Delphinium

Perianth of a single whorl of segments, the nectaries in small depressions near the carpels 1. Caltha

Perianth of 2 whorls of segments, i.e. the perianth and nectaries 7.

Petals or petaloid nectaries as large as or larger than perianth segments 17. Aquilegia

Petals or petaloid nectaries smaller than the perianth segments, if as long or longer then narrower 8.

Flowering stems leafless but with a whorl of bracts just below the terminal flower 9.

Flowering stems without such a whorl of bracts 10.

Perennials; leaves not finely divided; flowers white or yellow 4. Eranthis

Annuals; leaves very finely divided; flowers blue 5. Nigella

Perianth segments persisting around the group of follicles 3. Helleborus

Perianth segments deciduous in fruit 11.

Carpels (and follicles) united, at least towards the base.