Wood Ear (Auricularia fuscosuccinea)
Wood Ear Mushroom (Auricularia fuscosuccinea)
Wood Ear Mushroom (Auricularia fuscosuccinea) is a gelatinous, ear-shaped edible fungus native to the Americas, from the southeastern United States south to Argentina. It grows on decaying hardwood logs and is fully cultivable on sawdust and agricultural substrates. Most "wood ear" mushrooms found in the wild across the American South are this species — not the East Asian species that dominate grocery shelves.
Auricularia fuscosuccinea (Mont.) Henn. — Family Auriculariaceae — Order Auriculariales
Wood Ear Mushroom (Auricularia fuscosuccinea) is the native American wood ear — a species that most US foragers encounter regularly without realizing it is distinct from the Asian wood ears that dominate world trade. Formally recognized as a separate species from its East Asian relatives only through molecular analysis in 2013, Auricularia fuscosuccinea is the species you find on fallen sweetgum, oak, and box elder from Tennessee to Argentina. It is fully cultivable on hardwood sawdust, grows best at 30°C, and fruits prolifically after colonization — making it an ideal species for hobbyist and small-scale commercial cultivation.
What Is the Wood Ear Mushroom (Auricularia fuscosuccinea)?
The Wood Ear Mushroom is a member of the family Auriculariaceae (order Auriculariales), a group of jelly fungi characterized by gelatinous, rubbery basidiomes (fruiting bodies) and unusual 3-septate basidia — the spore-bearing cells divided into four chambers along their length, a structural feature unique to this order among the higher fungi. The name "wood ear" describes the mushroom's ear-shaped form, its habitat on wood, and its waxy-rubbery texture.
Auricularia fuscosuccinea was first described from Cuban material in 1842 by French mycologist Camille Montagne, who placed it in the genus Exidia as Exidia fuscosuccinea. In 1893, German mycologist Paul Christoph Hennings transferred it to Auricularia, recognizing that its stratified internal tissue layers and distinct medulla — a central layer of tissue running through the basidiome — aligned it with that genus rather than Exidia. The species epithet fuscosuccinea is Latin for "dusky amber" — from fuscus (dark brown, dusky) and succinus (amber) — a precise description of the translucent reddish-brown color of fresh material.
For most of the 20th century, American wood ear mushrooms were lumped together under the name Auricularia auricula-judae — the European and East Asian species — or simply labeled "wood ear" without species-level distinction. Looney et al. (2013), a phylogenetic study using both ITS and rpb2 (RNA polymerase II subunit) gene markers, demonstrated that what American foragers were calling "wood ear" actually comprised multiple distinct species, including A. fuscosuccinea and the newly recognized A. americana. This reclassification means that most pre-2013 ecological data and cultivation guides attributed to "wood ear" in the southeastern United States should be interpreted with caution at the species level.
As a white-rot saprotroph (a fungus that decomposes the lignin, cellulose, and hemicellulose of dead wood by secreting enzyme systems including class II peroxidases), A. fuscosuccinea derives all its carbon from lignocellulosic substrates — dead or dying hardwood in the wild, or sterilized sawdust and agricultural byproducts in cultivation. There is no mycorrhizal or parasitic requirement, no living host needed. This biology makes it straightforwardly cultivable using the same general approach as Pleurotus, Lentinula, or Ganoderma species.
Interested in this species? Out-Grow carries a liquid culture.
Wood Ear Mushroom (Auricularia fuscosuccinea) Liquid CultureHow Is Wood Ear Mushroom (Auricularia fuscosuccinea) Classified?
| Rank | Name |
|---|---|
| Kingdom | Fungi |
| Phylum | Basidiomycota |
| Subphylum | Agaricomycotina |
| Class | Agaricomycetes |
| Subclass | Agaricomycetidae |
| Order | Auriculariales |
| Family | Auriculariaceae |
| Genus | Auricularia Bull. ex Juss. |
| Species | Auricularia fuscosuccinea (Mont.) Henn. |
The basionym is Exidia fuscosuccinea Mont. (1842). The NCBI Taxonomy ID for the species is 160861. GBIF records approximately 1,250+ occurrence records globally, with Brazil holding the largest national dataset (~465 records). All major databases — MycoBank, Index Fungorum, NCBI, GBIF — agree on placement in Auriculariaceae, Auriculariales, Agaricomycetes.
The most comprehensive modern revision of the genus, Wu et al. (2021), analyzed 277 specimens from 35 countries using concatenated ITS and 28S rDNA markers and recognized 37 Auricularia species globally. That study placed A. fuscosuccinea as an Americas-centered taxon within the broader genus, resolving five major lineages in Auriculariaceae. A. fuscosuccinea is one of only three Auricularia species recovered as strictly monophyletic (a single, unified evolutionary group) in both ITS and rpb2 gene trees in the Looney et al. (2013) study, alongside A. nigricans and A. mesenterica.
How Do You Identify Wood Ear Mushroom (Auricularia fuscosuccinea)?
The single most important macroscopic character distinguishing A. fuscosuccinea from its closest US lookalike, Auricularia americana, is the presence of a medulla — a distinct internal layer of tissue visible in cross-section. The medulla is only reliably visible when fresh specimens are cross-sectioned and mounted in 5% KOH (potassium hydroxide solution). In A. americana, this medulla is absent; the tissue zones transition without that distinct layer. Field-only identification cannot reliably distinguish these species without microscopy.
Microscopic Features
| Feature | Measurement / Character |
|---|---|
| Spores | Smooth, allantoid (sausage-shaped); 11.0–13.6 × 6.5–8.5 µm; Q = 1.4–2.0; 1–2 large oil guttules |
| Basidia | 45–59 × 3.0–6.5 µm; 3-septate (divided into 4 cells); with oil guttules |
| Abhymenial hairs | 31–167 µm long × 3.8–6.8 µm wide; thick-walled; gregarious and tufted |
| Medulla | Distinctly present; often pigmented; 32–361 µm thick — key diagnostic character |
| Clamp connections | Present throughout context and zona pilosa |
| Hyphal system | Monomitic (one hyphal type) with clamp connections |
| Hymenium thickness | 41–86 µm |
Key Lookalike Species
Auricularia americana (deciduous unit)
Grows on same hardwood substrates in the same range. No medulla in cross-section (diagnostic); color more uniformly tan-brown without the rosy vinaceous hues; abhymenial hairs typically 67–136 µm. Molecular data (rpb2) required for confident separation. Both species are edible.
Auricularia americana (coniferous unit)
Found on conifers rather than hardwoods — a substrate distinction that is reliable in the field. May have a weak medulla. Both edible; the coniferous unit may represent a further distinct species pending formal description.
Auricularia nigricans
Much larger abhymenial hairs — 500–2,650 µm (hispid to hirsute), versus 31–167 µm in A. fuscosuccinea. Grows as larger, darker, more effusely spreading brackets. The hair length difference is visible under low magnification.
Auricularia scissa
Only known from Florida, Central America, and the Caribbean. Has a distinctly reticulate and merulioid hymenium (netted and wrinkled surface, unlike the smooth hymenium of A. fuscosuccinea) and a schizomedulla — the medulla dissociates when mounted in KOH, rather than remaining intact.
Exidia spp.
Black, wax-like jelly fungi with no pubescent hairs and no translucent brown tone. Not translucent or amber-brown. All Exidia lack the pubescent upper surface typical of Auricularia. Not a dangerous confusion — simply a different jelly fungus.
Dacryopinax spp.
Orange-yellow; spatula or fan-shaped; found on conifer wood rather than hardwood. Color, shape, substrate, and the absence of pubescent hairs all separate these immediately from A. fuscosuccinea.
Where Does Wood Ear Mushroom (Auricularia fuscosuccinea) Grow?
The Wood Ear Mushroom has a pan-American tropical to subtropical distribution, extending northward into the warm-temperate southeastern United States. In the US, it is most abundant along the Gulf Coast and in the southeastern states, with documented records as far north as Tennessee — representing the approximate northern inland limit of regular fruiting. It is the Auricularia species most commonly encountered by foragers across the American South.
| Region | Notes |
|---|---|
| Southeastern United States | Gulf Coast and SE states north to Tennessee; spring, summer, and fall fruiting, especially after rain events; also single records from Arizona and Washington State |
| Mexico | Tabasco, Tamaulipas, Chiapas, and other tropical states; widely documented |
| Central America and Caribbean | Costa Rica, Belize, Puerto Rico, Dominican Republic |
| Brazil | Most records (465+) of any country; 19 of 26 states; Atlantic Rainforest, Cerrado, Amazon Forest domains; year-round in tropical zones |
| Colombia, Ecuador, Peru | Documented; used as food in Colombia (Pauna, Boyacá); Ecuador as a food security crop |
| Argentina | Buenos Aires and Misiones provinces; reference collections in Looney et al. 2013 |
Auricularia fuscosuccinea is notable for its ecological flexibility. It fruits in primary forests, secondary growth, urban parks, and agricultural settings — essentially anywhere that fallen hardwood debris accumulates. This broad habitat tolerance reflects its character as a generalist white-rot decomposer with no specialized host requirements. Documented substrates include sweetgum (Liquidambar sp.), box elder (Acer negundo), sweet orange (Citrus sinensis), and many other hardwood species; it is not documented on conifers, which separates it ecologically from the coniferous unit of A. americana.
In the southeastern US, Tennessee represents the approximate northern inland limit — a biogeographically interesting position consistent with the "Out of the Tropics" hypothesis, which predicts that tropical lineages colonize adjacent temperate zones via their nearest warm-humid gateways. The Gulf Coast states provide exactly such a gateway for this otherwise pan-tropical American species.
Can You Cultivate Wood Ear Mushroom (Auricularia fuscosuccinea)?
Yes — Auricularia fuscosuccinea is fully cultivable. As a white-rot saprotroph with no living host requirement, it can be grown on sterilized or pasteurized lignocellulosic substrates using standard mushroom cultivation equipment. The species has been successfully fruited under controlled conditions in Brazil, Mexico, Colombia, Ecuador, Peru, and Argentina. It is not yet produced at commercial scale in the way that East Asian wood ear species are, but the published peer-reviewed literature provides sufficient data to reproduce fruiting reliably in a hobbyist or small-commercial setting.
Agar Culture
On agar media, A. fuscosuccinea prefers Potato Dextrose Agar (PDA), which consistently outperforms other media tested. Colony morphology on PDA is white to cream-colored with a flattened, appressed (pressed-flat) growth pattern — not particularly aerial. No distinctive pigmentation or odor is produced during agar growth. The optimal temperature across multiple independent studies is 30°C, at which high-performing Brazilian strains complete a 90 mm Petri dish in 7 days.
Agar Expansion
Use PDA or PDAE (enriched PDA) at 30°C in darkness. Expect 7–10 days to full plate colonization in vigorous strains. Brazilian strain CCIBt2381 produced the highest dry biomass on PDA (171.20 ± 10.01 mg at 7 days). Avoid MEA, which performs poorly.
Substrate Preparation
Best documented formula: 80% hardwood sawdust + 20% grass bran; moisture content 68%. Sterilize by autoclave at 121°C for 2 hours. Eucalyptus sawdust (the Brazilian standard) can be substituted with oak, beech, or mixed North American hardwood sawdust — no direct comparison data yet published for North American species.
Inoculation
Spawn rate: 2% (myceliated wheat grain spawn or liquid culture inoculum). Standard injection port technique for bag substrate or grain-to-sawdust transfer. Liquid culture inoculation onto grain spawn is expected to be fully functional based on the vigorous agar growth characteristics.
Spawn Run
Incubate at 30°C in the dark. Full colonization of 600 mL jar-scale substrate: 21–22 days. Full colonization of 2.5 kg block-scale bags: 25–34 days depending on strain. No special CO₂ management required during colonization.
Fruiting Induction
Cut or open the bag after full colonization. No cold shock or soaking required — primordia initiate naturally after the substrate surface is exposed to fresh air. The Drewinski 2024 study achieved fruiting without deliberate temperature drop, suggesting high tolerance for varied induction approaches.
Fruiting Conditions
Average fruiting temperature: 24°C (documented tolerance range: 7.4–35.5°C in uncontrolled conditions). Humidity: 64% average in published study (34–99% tolerance). CO₂: 659 ppm average (585–745 ppm range). First primordia: 14–21 days post-induction. First harvest: 35–45 days post-induction, strain-dependent.
Cultivation Parameters at a Glance
| Parameter | Value | Source |
|---|---|---|
| Optimal agar temperature | 30°C | Drewinski 2024 (Brazil); Coniglio 2021 (Argentina) |
| Best agar medium | PDA or PDAE | Multiple studies |
| Substrate colonization rate | 4.88–5.21 mm/day (eucalyptus sawdust) | Drewinski 2024 |
| Block colonization time | 25–34 days (2.5 kg bags at 30°C) | Drewinski 2024 |
| Fruiting temperature | 24°C average; tolerance 7–35°C | Drewinski 2024 |
| Primordia emergence | 14–21 days post-cut | Drewinski 2024 |
| First harvest | 35–45 days post-induction | Drewinski 2024 |
| Moisture content (substrate) | 68% | Drewinski 2024 |
| Biological efficiency (BE%) | Not yet published; comparable species: 84–148% | Research gap |
The wide temperature tolerance documented during fruiting is ecologically consistent with a species that fruits year-round in tropical and subtropical habitats. Unlike temperature-sensitive species requiring precise cold induction, A. fuscosuccinea appears highly forgiving — a practical advantage for cultivators working in uncontrolled or semi-controlled environments.
About the Out-Grow Wood Ear Mushroom Liquid Culture
Out-Grow's Auricularia fuscosuccinea liquid culture gives you a starting point for grain spawn production, agar expansion, or direct sawdust block inoculation. Because this is a true saprotrophic white-rot species, it colonizes lignocellulosic substrates readily without any living host requirement — unlike mycorrhizal or biotrophic species that cannot be conventionally cultivated.
The mycelium grows vigorously on PDA at 30°C, and the species tolerates a wide range of fruiting conditions. Inoculate grain spawn first for fastest expansion, then transfer to supplemented hardwood sawdust blocks. The 12cc syringe provides sufficient inoculum for multiple grain jars or direct block inoculation.
This is a native American species — the wood ear of the American South — not the East Asian cultivated wood ear. The cultivation parameters above are based on peer-reviewed data from Brazilian and Mexican research groups working specifically with A. fuscosuccinea, not generic "wood ear" guides describing A. heimuer or A. cornea.
What Bioactive Compounds Does Wood Ear Mushroom (Auricularia fuscosuccinea) Contain?
The chemistry of Auricularia fuscosuccinea is substantially less studied than that of its East Asian relatives. Several compounds have been documented specifically in this species; others are known from closely related Auricularia species and represent probable genus-level chemistry rather than confirmed species-specific findings. Each entry below is labeled by evidence quality.
Ergothioneine
Confirmed in speciesAn amino acid antioxidant found in many fungi. Lo et al. (2012) reported ergothioneine content in A. fuscosuccinea fruiting bodies at approximately 21.4 mg/kg dry weight — substantially higher than A. polytricha (1.4 mg/kg). Ergothioneine is a heat-stable, water-soluble antioxidant accumulated selectively by mammalian tissues. The functional significance of consuming it via dietary mushrooms is under active study.
β-Glucosidase (enzyme)
Confirmed in speciesConiglio et al. (2022) measured β-glucosidase (a cellulolytic enzyme — one that breaks down cellulose) activity of 12.2 ± 0.62 U/L in A. fuscosuccinea mycelium during solid-state fermentation of sugarcane bagasse. This enzymatic capacity is the basis for the species' potential in industrial bioprocessing of agricultural waste.
Phenolic compounds (substrate-derived)
Confirmed in speciesDuring solid-state fermentation of sugarcane bagasse, A. fuscosuccinea enzymes liberate phenolic compounds from the substrate: total phenolic content 507.5 ± 9.05 mg/L at day 20; DPPH radical inhibition (a standard antioxidant assay) peaking at 34.44% ± 11.20% at day 10. Note: these phenolics originate from the bagasse, enzymatically released by the fungus, not biosynthesized by it.
Nutritional profile (cultivated)
Confirmed in speciesDrewinski et al. (2024), dry weight basis: crude protein 10.73–12.11%; crude fiber 3.73–3.85%; crude fat 0.82–0.91%. Earlier data (Mau et al. 1998, Sánchez et al. 2018): protein 8.62–13.5%, fiber 11.69%. Variation across studies reflects strain differences, substrate composition, and harvest timing.
Polysaccharides (heteropolysaccharides)
Genus-level — not confirmed in speciesDocumented in A. auricula-judae: acidic heteropolysaccharide backbone with α-(1→3)-linked D-mannopyranose and pendant xylose, glucose, and glucuronic acid groups; 1,3-1,6-β-D-glucan content 16.8 g/100g; total yield 4.5–6.89%. These structures are probable in A. fuscosuccinea but have not been characterized at the species level.
Bioactivity (antioxidant, anticoagulant)
Genus-level in vitro — not confirmed in speciesFrom A. auricula-judae and A. auricula: DPPH EC50 ~0.08 mg/mL (methanolic extract); anticoagulant activity in multiple in vitro thrombosis models; antitumor activity in mouse macrophage cell lines at IC50 0.72 mg/mL. These findings are from related species, not A. fuscosuccinea, and all are in vitro or animal model data — no human clinical trials for any of these effects.
Is Wood Ear Mushroom (Auricularia fuscosuccinea) Safe to Eat?
Yes. The Wood Ear Mushroom is edible with a well-documented food history. It has been consumed by indigenous communities across its range in the Americas for generations, with no poisoning cases attributed to this species in the peer-reviewed literature. All published field guides and mycological sources treat it as edible.
| Concern | Evidence Status |
|---|---|
| Lethal toxins | None documented |
| GI toxins | None documented |
| Named toxins (species-specific) | None identified |
| Anticoagulant activity | Documented at genus level (in vitro); no clinical cases for this species; caution warranted for individuals on anticoagulant medications |
| Heavy metals | No species-specific data; general fungi caution — do not harvest from treated or contaminated wood |
| Allergenicity | Not specifically studied |
| Drug interactions | None documented; theoretical concern with anticoagulants based on genus-level data |
A genus-level note worth flagging: polysaccharides from related Auricularia species demonstrate anticoagulant properties in vitro (laboratory conditions). Individuals taking warfarin, heparin, or direct oral anticoagulants (blood thinners) should exercise caution with regular high-dose consumption of any Auricularia species, though no clinical case reports of interaction have been published for A. fuscosuccinea specifically.
Standard food safety practices apply: cook thoroughly before eating (cooking also improves the texture and digestibility of the gelatinous flesh); do not harvest from wood treated with preservatives, pesticides, or industrial chemicals; confirm species identity before eating, particularly to distinguish from the rarer A. scissa with its reticulate hymenium.
The ethnomycological record for this species is clear and consistent. Fidalgo & Hirata (1979) documented consumption by the Txicão and Txucarramãe peoples of Brazil's Xingu National Park — the oldest formal record of food use for this species in the Americas. Lacandón communities in Chiapas, Mexico; Colombian communities in Pauna, Boyacá; and Ecuadorian and Filipino communities all have documented food traditions involving this fungus.
What Makes Wood Ear Mushroom (Auricularia fuscosuccinea) Scientifically Remarkable?
The American South's Secret Wood Ear
Until Looney et al. (2013) applied molecular phylogenetics, essentially every "wood ear" record from the southeastern United States was filed under Auricularia auricula-judae — the European and East Asian species. The discovery that American wood ears are actually multiple distinct species means decades of ecological, nutritional, and cultivation data attributed to "wood ear" in this region are unreliable at the species level. A. fuscosuccinea has essentially been hiding in plain sight across the American South, systematically misidentified, since mycology began.
A Bioprocessing Organism
Research from Coniglio et al. (Argentina) demonstrated that A. fuscosuccinea produces a β-glucosidase enzyme cocktail capable of liberating phenolic compounds from sugarcane bagasse at a cost 12-fold lower than commercial enzyme preparations, and releasing 200–324% more protein than conventional extraction methods. This positions the species as a potential industrial platform organism for extracting value from agricultural waste — a role entirely separate from growing it as food.
Extraordinary Desiccation Tolerance
Like all Auricularia species, A. fuscosuccinea can lose up to 90% of its fresh weight by desiccation, becoming hard, shrunken, and nearly unrecognizable — then fully restore its original morphology, rubbery texture, and spore viability upon rehydration. The cellular mechanisms behind this tolerance — likely involving extracellular polysaccharide gels and aquaporin water channel proteins — are not fully characterized even in better-studied species. This property makes dried wood ear one of the most shelf-stable edible fungi commercially available.
The Biological Species Paradox
Wong (1993) showed through mating experiments that Brazilian A. fuscosuccinea and Asian populations labeled with the same name are reproductively isolated — they cannot interbreed. This means a single species name is applied to at least two distinct biological lineages separated by thousands of kilometers and an ocean. The pharmacological, nutritional, and cultivation literature from Asia labeled "A. fuscosuccinea" may describe a different, formally unnamed species. No new description has been published as of 2026.
Goeldi's Monkeys and Fungi
Goeldi's monkeys (Callimico goeldii), small New World primates from the Amazon, can consume up to 6 kg of Auricularia mushrooms — likely including A. fuscosuccinea — per individual. This exceptional primate-fungal relationship, noted in Fungi Academy curriculum, suggests the species plays a meaningful nutritional role in Amazonian primate ecology. This is one of the most remarkable documented primate-fungal feeding relationships known.
A White Strain with Skin-Care Properties
A naturally low-melanin ("white") strain of what is described as A. fuscosuccinea in Taiwanese cultivation literature shows moisture retention comparable to commercial sodium hyaluronate, stable viscosity at high temperatures, and antioxidant effects stronger than commercial Tremella fuciformis extract. Whether this white strain is a true albino mutant, a distinct cultivar, or even a taxonomically distinct entity has not been established — and white ear mushrooms command premium prices in East Asian markets, making this commercially significant.
Also available as a culture plate from Out-Grow.
Wood Ear Mushroom (Auricularia fuscosuccinea) Culture PlateFrequently Asked Questions About Wood Ear Mushroom (Auricularia fuscosuccinea)
What is the difference between Wood Ear Mushroom (Auricularia fuscosuccinea) and the wood ear sold in Asian grocery stores?
The wood ear sold in Asian grocery stores and used in East Asian cuisine is almost always Auricularia heimuer (black wood ear), A. auricula-judae (jelly ear), or A. polytricha — all East Asian species produced at commercial scale, primarily in China. Auricularia fuscosuccinea is the American species — native from the southeastern United States to Argentina. It is the wood ear you encounter on hardwood logs across the American South, but it is not yet produced commercially at the scale of its Asian relatives. The two groups are closely related and similar in appearance, texture, and culinary use, but represent distinct species with separate taxonomic histories.
How do I cultivate Wood Ear Mushroom (Auricularia fuscosuccinea)?
The species grows vigorously on hardwood sawdust (80% sawdust + 20% bran, 68% moisture, autoclaved at 121°C for 2 hours). Optimal spawn run temperature is 30°C in the dark; full block colonization takes 25–34 days at that temperature. After colonization, cut open the bag and allow fresh air exchange — primordia emerge naturally within 14–21 days without cold shock or deliberate humidity manipulation. First harvest typically occurs 35–45 days after bag opening. Because it is a saprotrophic white-rot species with no living host requirement, the basic cultivation approach is the same as for oyster mushrooms or shiitake.
Is Wood Ear Mushroom (Auricularia fuscosuccinea) the same as jelly ear or Judas's ear fungus?
No — these are closely related but distinct species. Jelly ear (Auricularia auricula-judae) is a European and East Asian species with a long history in traditional Chinese medicine and East Asian cuisine. Auricularia fuscosuccinea is the American species, formally separated by molecular phylogenetics in 2013. Before that reclassification, many American collections were incorrectly labeled as A. auricula-judae. Both species are edible and similar in texture, but A. fuscosuccinea tends toward a more vinaceous-brown (rosy) color, has a distinct internal medulla layer visible in cross-section, and is native to the Americas rather than the Old World.
What are the documented health benefits of Wood Ear Mushroom (Auricularia fuscosuccinea)?
The species has been consumed safely as food across the Americas for generations. Specifically confirmed in A. fuscosuccinea: ergothioneine content (21.4 mg/kg dry weight), a well-studied amino acid antioxidant, and a solid nutritional profile (10–12% protein, 3–4% fiber, less than 1% fat on a dry weight basis). The broader claims about cardiovascular benefits, anticoagulant effects, immune support, and cholesterol-lowering properties that appear in popular "wood ear" content are based on research into East Asian Auricularia species — primarily A. auricula-judae — and no randomized controlled human trial has been published specifically for A. fuscosuccinea.
How do I tell Wood Ear Mushroom (Auricularia fuscosuccinea) apart from Auricularia americana?
In the field, without microscopy, you largely cannot — and both are edible, so the safety stakes of confusion are low. The primary distinguishing character is the medulla: A. fuscosuccinea has a distinct internal tissue layer visible when fresh specimens are cross-sectioned and mounted in 5% KOH, while A. americana lacks this layer. Color can suggest the species — A. fuscosuccinea tends toward vinaceous-brown (rosy reddish-brown) while A. americana is more uniformly tan-brown — but this is not reliable for every specimen. Substrate can also help: A. fuscosuccinea has not been documented on conifers, while one unit of A. americana grows specifically on coniferous wood.
Where can Wood Ear Mushroom (Auricularia fuscosuccinea) be found in the wild in the United States?
In the wild, A. fuscosuccinea is most commonly found in the southeastern states — Louisiana, Mississippi, Alabama, Georgia, Florida, Tennessee, and Texas — on fallen or recently dead hardwood logs and branches, especially after significant rainfall. Sweetgum (Liquidambar), box elder (Acer negundo), and oak are among the documented hosts. It is most abundant in spring, summer, and fall. Isolated records exist from Arizona and Washington State, but the Gulf Coast and southeastern woodlands are the core of its US range. If you find an ear-shaped, reddish-brown gelatinous mushroom on a hardwood log in the American South, you have almost certainly found this species or A. americana.