Red chlorophyll fluorescence

Chlorophyll glowing red under UV light, here exemplified with hair moss (Polytrichum sp.). The second photo was taken without UV, just for comparison.

Fluorescence in green land plants and algae can be observed easily by illumination with a UV lamp. However, since mosses do not have a thick cuticle or hairs/trichomes, the red glow is more intense as with many vascular plants.

Chlorophyll fluorescence is also used scientifically to study phtosynthetic activity in living plants.