Bastard pennyroyal (Trichostema dichotomum) when ...

The image presents a comparative view of Bastard pennyroyal (Trichostema dichotomum) under two different lighting conditions: regular daylight and illumination by a 365 nm ultraviolet (UV-A) blacklight from Lick Creek Park, College Station, Texas.

**Image Layout**

The left side of the image features Bastard pennyroyal in its natural state under regular daylight. In contrast, the right side shows the same plant when exposed to UV-A light from a 365-nm blacklight. The background of both images is dark grey, allowing for a clear visual comparison between the two lighting conditions.

**Plant Appearance**

Under daylight, the Bastard pennyroyal plant appears green with small blue flowers. In contrast, under UV-A illumination, the leaves and stems exhibit a light blue coloration, while the flowers glow bright pink. This striking transformation highlights the unique effects of UV-A light on plant pigments.

**Key Observations**

* The image demonstrates how different lighting conditions can significantly alter the appearance of plants.
* UV-A light reveals subtle details in plant structure and pigmentation that would otherwise remain hidden under regular daylight.
* The use of a 365-nm blacklight allows for a controlled comparison between the effects of natural light and artificial ultraviolet illumination on plant appearance.

Overall, this image effectively illustrates the importance of considering lighting conditions when observing or photographing plants. By exposing Bastard pennyroyal to UV-A light, researchers can gain valuable insights into its biology and ecology. – AI vision