Arcyria, Comatricha, and Cribraria: Micro-ID Traits You Can Trust

These genera are often mixed in early-stage photos. Small size and color overlap are the main reasons.

Measurable traits table

Trait	Arcyria cues	Comatricha cues	Cribraria cues
Stalk scale	can include very short stalk forms in some taxa	hair-like stalk often obvious in dark mature forms	many taxa are very small overall
Head shape	bead to expanded fuzzy release forms	ball-like to elongated dark head forms	tiny delicate heads, often hard to resolve
Habitat context	dead wood frequent in notes	dead wood and small logs frequent	wood and bark, often missed without magnification
Microscopy need	medium	medium to high	high

When microscopy is mandatory

• Specimen height is sub-millimeter.
• Surface pattern is unclear in field photos.
• Candidate names belong to known species complexes.
• Mature opening state is missing.

Complex-level caution

The dataset includes repeated mentions of Arcyria and Comatricha variability. Treat single-image species names as provisional until structure and maturation are documented.

Workflow for better confidence

1. Capture habitat and substrate first.
2. Capture side profile with scale reference.
3. Return for maturation stage photo.
4. Use microscope image before final species naming.

Confidence note

High confidence: these genera are frequently confused without magnification. Medium confidence: species-level assignments in early stages.

Related reading: Immature vs Mature Slime Mold, Dehiscence Patterns, Focus Stacking for Myxomycetes.