Fauna
Fungus

Ash-tree Bolete

Boletinellus merulioides

Also known as Ash Bolete, Merulioid Bolete

Ash-tree boletes form a unique tripartite relationship with ash trees and subterranean aphids, feeding on honeydew produced by aphid colonies clustered around the tree roots. Fruiting bodies feature broad, wavy, brownish caps with short, off-center stems and an undersurface of yellowish, shallow, honeycomb-like pores that stain dull brown when bruised. As invasive emerald ash borers decimate native ash populations across North America, these distinctive fungi are becoming increasingly rare in their traditional forest and parkland habitats.

FungusAphid SymbiontWoodland
Ash-tree Bolete reference1 / 7
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—observations
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VulnerableConservation statusIUCN Red List categoriesLCNTVUENCREWEXVulnerableRed List categories, explained →
Key facts
Diet & preyAphid exudates and organic nutrients
Predators
  • Slugs
  • Fungus Gnat Larvae
  • Beetles
ThreatsHost tree loss from emerald ash borer infestation
HabitatsDeciduous woodlands, parks, and residential lawns near ash trees
Life spanFruiting bodies persist 1–2 weeks; underground mycelium lives perennially
Classification
  1. OrderBoletales
  2. FamilyBoletinellaceae
  3. GenusBoletinellus
  4. SpeciesBoletinellus merulioides
Range & activity
Range data is not available yet.
Safe observation
Interaction riskLow
  1. Low
  2. Moderate
  3. High
  4. Very high
Why interaction risk is low
Many wild mushrooms have toxic look-alikes; never eat wild fungi based on app identification alone.
What to notice
Look for broad, asymmetrical brown caps with shallow, honeycomb-like pores growing on soil near ash roots.
Support conservation
Leave fruiting bodies undisturbed to allow spore dispersal and help sustain remaining localized populations.
Responsible observation
  • Tree Association: Search near the base or root zone of mature ash trees during late summer and autumn.
  • Subterranean Sign: Look closely at soil beneath caps to spot dark fungal sclerotia wrapping aphid colonies.
  • Spore Dispersal: Leave mature caps in place to allow spores to spread to nearby healthy host trees.
Related species
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