Is Physarum polycephalum Wild in Europe: What Is Settled and What Is Debated

This article separates what is repeated in the community dataset from what remains unresolved.

What is settled in repeated community records

• The yellow plasmodium identity of Physarum polycephalum is well known.
• Community members repeatedly flag distribution claims as region-sensitive.
• Misidentification risk is high when relying on color-only photos.

What is debated in repeated community records

• How common true wild records are in parts of Europe.
• Which records are confirmed versus carried by legacy naming.
• Whether some observations belong to related taxa or species complexes.

Evidence tiers used here

• Tier A: repeated observation patterns in many independent posts.
• Tier B: plausible but region-limited claims.
• Tier C: unresolved claims requiring external verification.

The Europe wild-occurrence statement currently sits in Tier B to Tier C in this source set.

What would settle the debate

1. Consistent region-specific records with full morphology documentation.
2. Traceable voucher workflow for difficult cases.
3. Taxonomy-consistent naming in archived reports.
4. Clear separation from look-alike and renamed taxa.

Editorial policy for this topic

Do not present one-photo sightings as settled distribution facts. Use uncertainty labels until evidence moves from Tier C to Tier A.

Related reading: Taxonomy Name-Change Pitfalls, Community Claims Validation Protocol, Slime Mold Look-alikes.