Armillaria mellea, the honey mushroom, grows in dense clusters of honey-yellow caps with fused stem bases on wood or from buried roots. It is a major parasite and decomposer of trees, causing Armillaria root rot in hundreds of woody plants and spreading by black, bootlace-like rhizomorphs. It belongs to a complex of similar species that can be hard to separate without mating tests or DNA.
Edible only when thoroughly cooked; it is mildly poisonous raw and upsets some people even when cooked, especially specimens from buckeye or hemlock. Avoid alcohol before and after eating it. The deadly Galerina marginata can grow on the same wood; it has a dark brown spore print, whereas honey mushrooms print white, so always take a spore print. Pholiota species also print brown.
Never eat a wild mushroom based on a web page — confirm with an expert.
Mycology is an evolving science: names, classifications and safety information change as research advances. Entries are compiled from cited sources and reviewed, but may be incomplete or out of date — check the sources, and never rely on this library alone to identify or eat a mushroom.
Habitat
Parasitic and often pathogenic on living hardwoods, occasionally conifers, and saprotrophic on stumps and dead wood, causing a white rot. Fruits in dense clusters at trunk bases, on stumps or from roots; prefers moist, heavy soils. Season: Mainly autumn after rain; nearly year-round in warm climates.
Distribution
Northern temperate regions of Europe, Asia and North America. In North America the species in the strict sense occurs mainly in the eastern half of the continent, from about the Great Lakes to the Gulf and East Coasts, with reports from northern California; similar species (A. gallica, A. calvescens, A. ostoyae) overlap its range.
Characteristics
Cap: 3–15 cm; convex and often squarish-sided when young, becoming flat, sometimes with an umbo; honey-yellow to golden, fading to brownish; smooth and sticky when wet, sometimes with a few small dark scales near the centre. Gills: Attached or slightly decurrent, close to fairly distant; whitish, later spotting pinkish to brownish. Stem: 5–20 cm long, 0.5–3.5 cm thick; tough, tapering to the base, bases fused in clusters; whitish above, brownish to dark below. Ring: Persistent, white, with a pale yellow edge. Spore print: White; spores ellipsoid, about 6–9 × 4–7 µm, inamyloid; basidia without basal clamps. Other: Black rhizomorphs; mycelium and rhizomorphs glow during active growth.
