Stachybotrys chartarum is a greenish-black mold that grows only on cellulose-rich material kept wet for an extended period, and it is the species most people mean when they say "black mold."
What is Stachybotrys?
Stachybotrys is a slow colonizer that needs sustained moisture and a high-cellulose substrate such as drywall paper, ceiling tile, or wet wood, which is why its presence is a marker of a chronic water problem rather than a one-day spill. It produces mycotoxins, and its spores are heavy and slimy, so they do not aerosolize as readily as lighter genera; that means a spore trap can miss active Stachybotrys growth even when a wall is covered in it. The CDC is direct that "black mold" is not a special toxic category requiring different handling, and that there is no proven link between Stachybotrys and the rare conditions once attributed to it (CDC, About Mold).
Why it matters to a mold inspection
Because Stachybotrys spores release poorly into the air, the reliable way to confirm it is a tape lift or bulk sample on the visible growth, not air sampling alone, and a low air count is a textbook false negative when there is visible black growth. The EPA's guidance is that the remediation answer is the same regardless of species: fix the moisture and remove the growth, because no safe airborne concentration is defined (EPA, Mold and Health). For homeowner-facing context, see is black mold dangerous and what is Stachybotrys.
MoldMind links a visible-growth photo to the surface-sample result and the species ID, so a Stachybotrys finding is documented by the evidence that actually confirms it.
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Sources
- CDC, About Mold: "black mold" is not a special toxic category; respond to moisture and visible growth.
- EPA, Mold and Health: no safe airborne concentration; the remediation answer is moisture control and removal.