The compilation of species will continue to be updated at irregular intervals. All species listed here have been documented, and links are added whenever I can find spare time for updating. These images are made for illustrative purposes, not as artistic statements per se. However, there are lots of food for thought in the convoluted ways Nature expresses itself, so for once the artist can step backand let the subjects speak for themselves. "Das Ding an Sich" to paraphrase Kant, or Eigenvalue of Nature.

If you are unfamiliar with the botany, just select any species indicated as having a "strong" response to learn how this looks. Potentilla anserina may constitute an introductory example. In case you wonder about the family and species selection, these are plants readily available to me.

However, not all species have the typical bull's-eye UV pattern, which may be confined to symmetrical flowers. Nevertheless flowers may exhibit a virtually endless variety of spectral signatures. Just take a look at this modest plant, Glechoma hederacea, to get an impression of the near bewildering spectral diversity that exists.

The UV range of the spectrum has no predefined colours, so we are free to assign any colour we like. There are no rules set in stone for this at all. I set out my UV work using film, so in principle would like the "film UV colours" (blue with UV absorbance often shown in reddish hues) to prevail. Different spectral response of the UV bandpass filters applied in these years, in conjunction with changing behaviour of the digital cameras and their RAW-file converters, have made this aim impossible to uphold. Thus, don't compare colours, compare patterns. I'm currently writing a tutorial on how the UV "colours" are created and how they should be interpreted, but for the time being, just enjoy the images like the pollinators enjoy their targeted flowers.

UV fluorescence may be a common trait to most flowers, but might be of temporary occurrence for parts of the flower. Anthers, style, and pollen grains occasionally are seen to fluoresce. Strong fluorescence has been noted from nectar glands (Angelica sylvestris) and several other species. Some species show fluorescence of the non-fertilised stigmas, but this trait is difficult to document with my normal technical approach. Fluorescence from outside of the bracts is exhibited by some species. As far as the photography is concerned, the main issue with flower fluorescence is its transient behaviour. It may be present, but the flowers collected for photography don't appear to fluoresce simply because the floral development is in the "wrong" stage. With fluorescent pollen grains, their size often are at or below the detection limit unless quite high magnification is employed, thus calling for a true photomacropgraphic approach. The fluorescing pollen of Mirabilis jalapa (Four o'Clock) has been documented using this method.

In case you are curious as to why the species might have these patterns, read this to learn more. UV-absorbing substances (flavonyl glucosides) are instrumental in bringing about the fascinating pollinating guide patterns. UV marks on flowers are but a logical extension of the visual pollinating clues provided by evolution in Nature. When a flower is stated to lack UV marks, it simply means the signals emitted are directed towards pollinators which can "see" in alternate spectral bands, outside the UV range. If the flower absorbs UV all over the floral parts, it may appear visually in a "UV-complementary" colour even to pollinators capable of seeing in UV. We can only speculate as to the rendition of that complementary colour, but if say the insect is modelled as seeing UV as "blue", blue as "green", and green as "red", then the UV complementary would be yellow. Thus, a UV-absorbing yellow flower still would come across as "yellow" even for an insect (or so it might seem, but who are we to know such things anyway).

A final word of warning is that UV photography as such has lots of technical pitfalls and issues. You have to make absolutely sure your camera really records UV patterns, and in order to ensure this, careful testing of your setup is necessary. This has become even more important in the digital era, as outlined elsewhere in my UV/IR tutorial. Read in particular about the issues with IR contamination described there.

(Strong, intermediate etc. refer to a UV-visible bull's-eye pattern of the flower. Other patterns may appear as duly noted)

Asteraceae

Brassicaceae

Campanulaceae

Caprifoliaceae

Convolvulaceae

Crassulaceae

(yellowish green, red tentacles)

Ericaceae

Fabaceae

Geraniaceae

Lamiaceae

Nymphaeaceae

Primulaceae

Ranunculaceae

Rosaceae

Scrophulariaceae

Solanaceae

Violaceae

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