Flowers of St. Andrew cross (Hypericum, Ascyrum ...

The image presents a striking comparison between the appearance of flowers under normal lighting conditions and their fluorescence when exposed to ultraviolet (UV-A) light at 365 nanometers.

**Upper Image: Natural Light**

* The upper image displays two yellow flowers with five petals each, showcasing their natural coloration.
* The stems are green, while the leaves surrounding them appear dark green or almost black in color.
* The background is a solid gray color, which suggests that the photograph was taken indoors or in a controlled environment.

**Lower Image: UV-A Blacklight**

* In contrast, the lower image reveals the same flowers under 365 nm ultraviolet (UV-A) blacklight illumination.
* The yellow petals of both flowers exhibit a vibrant pinkish-red fluorescence, with some areas displaying a more intense coloration than others.
* Notably, only the middle part of each flower petal exhibits this effect, while the edges and tips remain unchanged from their natural appearance.
* Additionally, the stems and leaves also appear to fluoresce, although not as intensely as the petals.

**Overall Observation**

The image highlights the unique property of certain plant species to exhibit fluorescence under UV-A light illumination. This phenomenon is likely due to the presence of specific compounds within the flowers that absorb light in the UV range and re-emit it at longer wavelengths, resulting in their characteristic colors. The observation of this effect may have practical applications in fields such as botany or horticulture, where understanding plant physiology could lead to new insights into plant growth and development.

**Conclusion**

In conclusion, the image provides a fascinating comparison between the appearance of flowers under natural light and their fluorescence when exposed to UV-A blacklight illumination. The observation of this effect offers valuable insights into the properties of these plants and may have significant implications for various fields of study. – AI vision