Where it grows

• Decaying leaves and plant litter
• Soil, compost and mulch
• Damp indoor materials

How to recognize it

Mold spores are identified by colour, wall thickness, surface ornament and the pattern of internal dividing walls. Many genera can only be separated with those features together, so we publish at the level the evidence supports.

Allergy relevance

Outdoor spore counts often exceed pollen counts in humid weather, and mold sensitivity is an established asthma risk factor.

Where it's found

Worldwide and in every US state.