The Mystery of the Glowing Moss

Native plant enthusiast Shirley Henderson couldn’t believe her eyes when she first spotted patches of glowing moss at Thirlmere Lakes, 60km west of Sydney city.

The fluorescent moss seemed to be creating its own light, continuing to shine even when shaded from sunlight.

Adding to the intrigue was the growth pattern of the moss, surrounding the entrance of a large wombat hole in a bright, green ring shape.

Shirley knew just who to contact for help solving this botanical mystery. As a member of Landcare she has a good knowledge of local nature and regular contact with experts at the Botanic Gardens. Our science team receives hundreds of public enquiries every month asking for help identifying plants, drawing on the knowledge of our botanists and horticulturalists.

Photos and a small piece of moss were given to bryophyte researcher Dr Matt Renner who studied the sample under a microscope looking for key identifying features.

Moss can be difficult to tell apart and in this case Matt had to look at individual cells to finally conclude the species was Polytrichadelphus magellanicus.

This moss is found throughout the southern hemisphere and its apparent adaptation to Australian wombat holes makes sense given its preferred habitats are clay banks, roadside cuttings, trackside banks and stream sides in other parts of the world.  

Not a lot is known about why some moss, fungi and algae sometimes make their own light. The technical term for this ‘living light’ is bioluminescence, a phenomenon mostly associated with creatures of the sea. Bioluminescence is caused by a chemical reaction involving a chemical called luciferin (from the Latin ‘lucifer’ meaning ‘light bringer’), a type of biological light emitting pigment.

Dr Renner has pointed at that in this instance it is unlikely that the moss identified is the source of the bioluminescence but suggests there could be a glowing fungi species living in partnership with the moss. It is also possible that the bright colour seen is just a trick of the light reflecting off healthy moss growing in perfect conditions.

While the eye-catching green glow is yet to be fully explained, Shirley Henderson was thrilled to have her moss identified and the wombats of Thirlmere Lakes are enjoying their well decorated burrows.

Learn more about this fascinating phenomenon at Science at The Calyx: Luminescence