# Melanoleuca melaleuca
**Melanoleuca melaleuca** ((Pers.) Murrill) is a species of gilled mushroom in the genus *Melanoleuca*, family [Tricholomataceae](https://www.edgepedia.org/tricholomataceae), and the type species of that genus.[1](https://pubmed.ncbi.nlm.nih.gov/34788201/) It is a small to medium, brown-capped 'cavalier' mushroom of grassland and woodland edges in Europe and North America, and it is so similar to its close relative *Melanoleuca polioleuca* that the two cannot be separated reliably in the field.[2](https://mail.first-nature.com/fungi/melanoleuca-melaleuca.php)
| Key fact | Detail |
|---|---|
| Classification | Fungi, Basidiomycota, Agaricomycetes, Agaricales, Tricholomataceae[3](https://www.gbif.co.id/spesies/melanoleuca-melaleuca) |
| Status | Type species of the genus *Melanoleuca*[1](https://pubmed.ncbi.nlm.nih.gov/34788201/) |
| Basionym | *Agaricus melaleucus*, described by Christiaan Hendrik Persoon in 1801; transferred to *Melanoleuca* by William Alphonso Murrill in 1911[2](https://mail.first-nature.com/fungi/melanoleuca-melaleuca.php) |
| Cap | 3.5 to 7 cm across, smooth and slightly greasy, mid to dark gray-brown when moist, paler in dry weather[2](https://mail.first-nature.com/fungi/melanoleuca-melaleuca.php) |
| Spores | Ellipsoidal, densely warty, amyloid, 7–8 × 4–6 µm; spore print very pale cream[2](https://mail.first-nature.com/fungi/melanoleuca-melaleuca.php) |
| Cystidia | Gill-edge cystidia of the pointed fusiform kind found in *M. polioleuca* are lacking entirely in *M. melaleuca*[2](https://mail.first-nature.com/fungi/melanoleuca-melaleuca.php) |
| Habitat and season | On soil in permanent pastures, lawns, and parks, sometimes among leaf litter in broadleaf woodland; July to November in Britain and Ireland[2](https://mail.first-nature.com/fungi/melanoleuca-melaleuca.php) |
## Naming and taxonomic history
Persoon established the basionym *Agaricus melaleucus* in 1801, in the era when most gilled mushrooms were placed in a single large genus *Agaricus*.[2](https://mail.first-nature.com/fungi/melanoleuca-melaleuca.php) The species was later placed in *Tricholoma* as *Tricholoma melaleucum* (Pers.) P. Kumm., and the American mycologist William Alphonso Murrill (1869–1957) transferred it to its present genus in 1911.[2](https://mail.first-nature.com/fungi/melanoleuca-melaleuca.php) Synonyms include *Melanoleuca graminicola* and *Melanoleuca vulgaris*.[2](https://mail.first-nature.com/fungi/melanoleuca-melaleuca.php)
The genus name itself has a tangled history. Patouillard erected *Melaleuca* Pat. in 1887, but because that name was already used for a genus of plants, he changed it to *Melanoleuca* Pat. in 1897.[4](https://www.sciencedirect.com/org/science/article/pii/S1314405721000537) The name combines the [Ancient Greek](https://www.edgepedia.org/ancient-greek) *melas* (black) and *leucos* (white), a reference to the gray-brown caps over whitish gills typical of the genus; as often happens with a type species, the epithet *melaleuca* essentially restates the generic name.[2](https://mail.first-nature.com/fungi/melanoleuca-melaleuca.php)
## Identification
The caps are initially convex with an incurved margin, eventually flattening or becoming shallowly depressed with an umbo; the surface is smooth and slightly greasy, mid gray-brown to dark gray-brown when moist and paler in dry weather.[2](https://mail.first-nature.com/fungi/melanoleuca-melaleuca.php) The gills are sinuate, white turning creamy-gray with age.[2](https://mail.first-nature.com/fungi/melanoleuca-melaleuca.php) Typically twice the width of the cap or more, the stipe measures 4 to 9 cm in length and 0.5 to 1 cm across, slightly bulbous at its base, whitish, and marked with light brown lengthwise fibers; it bears no ring.[2](https://mail.first-nature.com/fungi/melanoleuca-melaleuca.php) The odor and taste are not distinctive.[2](https://mail.first-nature.com/fungi/melanoleuca-melaleuca.php)
Microscopy is required for a confident identification. The spores are ellipsoidal, densely warty, and amyloid (staining blue-black in Melzer's reagent), measuring 7–8 × 4–6 µm, and the spore print is very pale cream.[2](https://mail.first-nature.com/fungi/melanoleuca-melaleuca.php) The critical distinction from *Melanoleuca polioleuca*, the Common Cavalier, is microscopic: *M. polioleuca* has more elongated spores (a larger length-to-width ratio) and pointed, fusiform gill-edge cystidia, which are lacking entirely in *M. melaleuca*.[2](https://mail.first-nature.com/fungi/melanoleuca-melaleuca.php) The two are macroscopically indistinguishable with certainty.[2](https://mail.first-nature.com/fungi/melanoleuca-melaleuca.php)
## Why the species is hard to delimit
*Melanoleuca* is a genus with limited morphological characters, and different taxonomists have interpreted the same features differently, producing conflicting classifications.[5](https://www.frontiersin.org/articles/10.3389/fmicb.2019.02167/full) The scale of the disagreement is large: Index Fungorum lists 422 validly published species in the genus, while Kirk and colleagues' 2008 *Dictionary of the Fungi* accepted only 50.[5](https://www.frontiersin.org/articles/10.3389/fmicb.2019.02167/full) In North America the concept of *M. melaleuca* itself has been described as incoherent, with authors applying European names on a best-fit basis; some follow Kühner's 1978 concept in which *M. melaleuca* lacks prominent cystidia, while most other North American and European authors describe a species with harpoon-like cystidia.[6](https://www.mushroomexpert.com/melanoleuca.html)
Molecular data have begun to stabilize the group. A 2021 revision of the European taxa of subgenus *Melanoleuca*, the lineage with well-developed macrocystidia to which *M. melaleuca* belongs, delimited species using macro- and micromorphological characters together with multilocus DNA data from the internal transcribed spacer (ITS), the second largest subunit of [RNA polymerase I](https://www.edgepedia.org/rna-polymerase-i) (*rpb2*), and translation elongation factor 1-alpha (*tef1*) genes, based on both type material and recent collections.[1](https://pubmed.ncbi.nlm.nih.gov/34788201/) These taxa formed 10 phylogenetic clades, recognized as 11 separate species including *M. melaleuca*, and the study discussed *M. melaleuca* as the type species of the genus.[1](https://pubmed.ncbi.nlm.nih.gov/34788201/) Earlier ITS-based work had already shown the genus to be monophyletic and supported only two emended subgenera, *Urticocystis* and *Melanoleuca*, with the previously recognized cystidia-less subgenus *Acystis* shown to be polyphyletic.[7](https://iris.unito.it/handle/2318/91488)
## Distribution and ecology
*Melanoleuca melaleuca* is widespread and fairly common in Britain and Ireland, occurs throughout mainland Europe, and is found also in North America.[2](https://mail.first-nature.com/fungi/melanoleuca-melaleuca.php) It fruits on soil in permanent pastures, lawns, and parks, and sometimes among leaf litter in broadleaf woodland, from July to November in Britain and Ireland.[2](https://mail.first-nature.com/fungi/melanoleuca-melaleuca.php) More than thirty species of the genus are recorded from Britain and Ireland, most with brownish caps and white gills, and separating them is described as a task for specialists.[2](https://mail.first-nature.com/fungi/melanoleuca-melaleuca.php)
Some cavaliers are reported to be edible but unremarkable; because species in this genus are notoriously difficult to identify, field guides recommend that they not be collected for food.[2](https://mail.first-nature.com/fungi/melanoleuca-melaleuca.php)
## References
1. [Multilocus phylogeny and taxonomy of European Melanoleuca subgenus Melanoleuca (PubMed)](https://pubmed.ncbi.nlm.nih.gov/34788201/)
2. [Melanoleuca melaleuca, a cavalier mushroom (First Nature)](https://mail.first-nature.com/fungi/melanoleuca-melaleuca.php)
3. [Melanoleuca melaleuca, Biodiversitas Nusantara / GBIF](https://www.gbif.co.id/spesies/melanoleuca-melaleuca)
4. [Three new Melanoleuca species from north-eastern China (ScienceDirect)](https://www.sciencedirect.com/org/science/article/pii/S1314405721000537)
5. [Phylogenetic Analyses of Some Melanoleuca Species in Northern China, Frontiers in Microbiology (2019)](https://www.frontiersin.org/articles/10.3389/fmicb.2019.02167/full)
6. [The Genus Melanoleuca, MushroomExpert.Com](https://www.mushroomexpert.com/melanoleuca.html)
7. [A preliminary ITS phylogeny of Melanoleuca, with special reference to European taxa (University of Turin IRIS)](https://iris.unito.it/handle/2318/91488)
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*Topic: Encyclopedia › Life and health › Microorganisms and fungi › Fungi and mycology › Basidiomycete taxa › Agaricomycetes › Agaricales › Tricholomataceae and allies › Melanoleuca*
*Initially written Sep 17, 2026 · Reviewed: Oct 21, 2026 · Edited: Oct 15, 2026; Oct 21, 2026 · Last review: Oct 21, 2026*
*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*
License: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license