Study
The fungus Armillaria bulbosa is among the largest and oldest living organisms
Smith, Myron L.; Bruhn, Johann N.; Anderson, James B.
Nature, 1992
Fungal isolates collected across a Michigan hardwood forest were compared by mating-type, mitochondrial DNA and nuclear markers to determine how many genetically distinct individuals were present.
- Studied in
- Armillaria gallica
- Sample size
- isolates sampled across a 15-hectare Michigan forest
A single genetic individual occupied at least fifteen hectares, weighed an estimated hundred tonnes or more, and — from growth-rate estimates — had persisted for something on the order of 1,500 years.
What it means
The authors' reading, and ours. Where they differ, that difference is the point.
How the authors put it
Fungal genets can be among the largest and longest-lived organisms known.
How NatureHQ reads it
The result is genuine and the framing needs care. Everything rests on what counts as an individual: this is one genetically uniform, physically connected mycelium, which is a defensible definition and not the only one, and the mass and age are extrapolations rather than measurements. The deeper point survives all the caveats — a fungus is mostly an underground network, and the mushroom is a temporary reproductive structure, which is why the size is surprising at all.
- Mass and age are estimated from growth rates and sampled extent, not measured.
- Whether a spatially continuous genet is one individual is a definitional question, not an empirical one.
- Later work found larger Armillaria genets elsewhere, so the superlative has moved.
What this study is used for on NatureHQ
One study can inform several subjects. Here is everywhere this one is cited.
Published by: Nature PortfolioPublished in a Nature Portfolio journal.
This reference was resolved automatically against Crossref on 2026-08-11.
NatureHQ summarises research in its own words and does not reproduce published text. Reviewed 2026-08-09.