Ultraviolet Flowers: Geranium pratense

Geranium pratense L.

Geraniaceae

Visible light
(L37 filter)

UV light
(Hoya U-360, SB-140)

Geranium pratense. IR light

IR light
(Wratten 89B, SB-140 with Wratten 87)

All images

A large-flowered species with a strong UV signature in the fashion of a typical bull's-eye pattern. In addition, the radiating veins in the petals also absorb UV strongly.

Meadow Crane's Bill has larger and more bluish-hued flowers than its close relative, Wood Crane's Bill (G. sylvaticum). Interestingly, although many people find these species to be difficult to differentiate, their UV markings are obviously dissimilar. Even near-IR reflectance is lower for G. pratense, but still sufficient to mislead colour rendition of the flower hues by film or digital recording.

I've recorded UV signature of this species several times, and it has evidently a quite variable "bull's eye" UV pattern. Some strains show virtually no centre spot, others do prominently (as depicted above). All flowers have strongly UV-absorbing veins on the petals, however.