Ruby Bonnets: A Glowing Discovery in Peel Forest

Testing the glow of Cruentomycena viscidocruenta in New Zealand for the first time.

Cruentomycena viscidocruenta—try saying that three times fast without summoning something from the void. Most people stick to the easier name: Ruby Bonnet.

Cruentomycena viscidocruenta

Etymology

The name comes from Latin and Greek roots, describing both its color and texture. Cruento- and cruenta come from cruentus, meaning "bloodstained," a nod to its red color.

Mycena is from the Greek mykēs (μύκης), meaning "fungus." Viscido- comes from viscidus, meaning "sticky" or "slimy," referring to its gelatinous stipe.

Put together, the name essentially means "bloodstained Mycena with a sticky, blood-red appearance"—a pretty apt description.

Gills of Cruentomycena viscidocruenta

I first met these mushrooms through my friend Cath Smith over five years ago at Fraser’s Gully in Dunedin, completely unaware at the time that they had a secret. They glow in the dark.

Cruentomycena viscidocruenta mushroom growing on a leaf shot at f/2.8 - ISO12800 - 60" to capture bioluminescent mycelium

The Ruby Bonnet is easily recognized by its vivid red cap and a sticky, translucent stipe—something it shares with Roridomyces, a genus well-known for bioluminescence.

Photographing Bioluminescent Roridomyces

I’d first read about another species, Cruentomycena orientalis, glowing in Japan, and that got me wondering.

Similar glowing Cruentomycena appear in Malaysia, and my friend GS Tan tracked one down outside Kuala Lumpur and confirmed its mycelium glows.

Ever since, I’ve been itching to get back to New Zealand to see if Cruentomycena viscidocruenta could glow too. That chance finally came during a foray in Peel Forest. Walking along the Fern Trail, I spotted at least a hundred of them—bright red caps dotting twigs, fuchsia roots, and leaves. Perfect test subjects.

Cruentomycena viscidocruenta

With experience photographing glowing fungi, I knew the gamble: sometimes the glow is in the mycelium, sometimes in the fruiting body, and sometimes it just doesn’t show up at all.

Faint glow of mycelium on a twig

I remembered a trip behind Batu Caves where an entire leaf had lit up, while twigs—though they sometimes glow—are usually faint. Not wanting to wait seven hours for nightfall, I improvised. Back at camp, I converted the boot of my car into a makeshift darkroom, draping blankets over the windows and setting up a black box to block out stray light.

The Other Side of Batu Caves - Exploring Gombak-Hulu Langat Geopark

With my camera connected to my OI.Share app for a remote shutter release, I shot at f/2.8 and ISO12800, set the exposure to a minute, and waited. When the screen refreshed, a bright green glow appeared. Success.

This is the first recorded instance of Cruentomycena viscidocruenta glowing in New Zealand, as far as I can tell.

A little red mushroom with a hidden green secret.

Cruentomycena viscidocruenta on a leaf exhibiting bioluminescent mycelium.