The yellow anthers set off the dark colored petals, making for a pleasing flower.  I would likely choose this one as my favorite peony of the Black Pirate group. It is not as dark as ‘Corsair’ or ‘Black Douglas’. The colors of the stigmas, filaments, and sheath can be used to distinguish it from ‘Black Pirate’. Unfortunately the flowers tend to hang down.

It has pollen and is in the parentage of ‘Hephestos’ (Daphnis, 1977).

Cultivar: Thunderbolt
Year: 1948
Seedling No: 13014
Group: Black Pirate
Flower: Color: very dark crimson/maroon; no noticeable flares
Form: single, two rows of petals, 10-13
Blooms: Week 5
Carpels: 4, green
Stigmas: bright dark pink
Sheath: dark red (“blackish-purple-Reath and Saunders)
Stamens: filaments dark red
Plant: Habit: wide rounded bush
Foliage color: medium green
Foliage form: slightly more narrow than most
Height: 34″ on 8 year plant
Recommendation: Recommended especially if you like dark colors
Availability: Few nurseries specializing in woody peonies