Calcium Crystals and Didymium ID: Hand Lens Checklist

In this dataset, large visible crystals on the outer wall are repeatedly linked with Didymium-like identifications. Crystal condition depends on development and drying.

Hand lens checklist

Use at least 10x magnification. If available, 20x improves confidence.

1. Confirm fruiting body is mature enough to inspect.
2. Inspect peridium for spark-like angular crystals.
3. Check stalk and base shape.
4. Record whether specimen is still wet or already dry.
5. Re-check after controlled drying if features are unclear.

Didymium vs Physarum field rule in repeated community records

• Didymium pattern in the group notes: crystalline, shard-like lime appearance.
• Physarum pattern in the group notes: more granular or chalk-like lime presentation.

Treat this as a field heuristic, not a single-character proof.

Why drying stage matters

Interrupted or abnormal drying can hide or blur lime features. If a specimen dries badly or is re-wetted, diagnostic structures may fail to present clearly.

Confusion matrix

Observed cue	Didymium-leaning	Physarum-leaning	Notes
Angular sparkling crystals	yes	no	strongest field cue in this dataset
Powdery/chalk-like surface	possible	yes	needs additional structure checks
Very short hidden stipe with sessile look	possible in some Didymium notes	possible in other taxa	use multiple cues
Color alone	no	no	not diagnostic

Confidence note

This guide reflects repeated community-level morphology patterns. Final species names still require full structure context and often microscopy.

Related reading: Dehiscence Patterns, Arcyria, Comatricha, and Cribraria, Moist Chamber Setup.