Smith's amanita (Amanita smithiana)
🏷️ Description
Meet Amanita smithiana – A Beautiful but Deceptive Fungus! 🍄 Its elegant white cap, often dusted with soft, powdery remnants of its universal veil. This uncommon mushroom thrives in Japan and shares striking similarities with other toxic Amanitas across the globe. Its cap, measuring up to 6.69 inches (17 cm) wide, can lose its delicate scales in rainy conditions, making it dangerously easy to mistake for prized edible mushrooms like the matsutake (Tricholoma murrillianum).
⚠️ Beware the Deception! Though alluring, A. smithiana is a toxic mushroom. Ingesting it can lead to severe gastrointestinal distress within hours, followed by acute kidney damage days later. The culprits? Toxins like chlorocrotylglycine and allenic norleucine, which have been linked to poisonings in Japan and beyond. Fortunately, with prompt medical care—including hemodialysis—most victims recover fully.
🌲 Where to Find It? This species prefers coniferous and broadleaved forests, where it emerges in late summer to early fall. It’s part of the Lepidella subgenus and is closely related to other toxic Amanitas found in North America and Europe.
📜 Taxonomy: Amanita smithiana was described by Dutch mycologist Cornelis Bas in 1969. The specific epithet honors mycologist Alexander H. Smith, who collected the type specimens from Washington in 1941.
🔎 Identification
🧢 Cap:
Size: 1.97 to 6.69 inches (5 to 17 cm).
Shape: Convex to plano-convex.
Color: Whitish to cream (faintly brownish in dry weather).
Texture: Covered in soft, powdery veil material, sometimes forming whitish warts 🤍, which may wash away with rain 🌧️.
Surface: Moist to slightly sticky when fresh.
🌿 Gills:
Attachment: Free from the stem.
Spacing: Close to crowded.
Color: Whitish to cream.
Edges: Fimbriate (fringed).
Development: Initially covered by a white, powdery partial veil.
📏 Stem:
Size: 2.36 to 7.09 inches (6 to 18 cm) long, up to 1.38 inches (3.5 cm) cm thick.
Shape: Spindle-shaped when uprooted, with a swollen base extending into a root-like projection.
Texture: Shaggy when young, with remnants of a ragged or missing ring.
Surface: White, sometimes with cottony veil fragments that can discolor tan to brown.
Volva: Poorly developed, appearing as concentric bands of veil fragments that turn buff to pinkish brown.
🍄 Flesh:
Color: White 🤍.
Reaction: Does not change color when sliced.
👃 Odor & Taste:
Odor: Mild when young but can become unpleasant with age.
Taste: Mild.
🎨 Spore Print: Color: White ⚪.
🌲 Habitat & Ecology: Mycorrhizal with conifers, especially Douglas-fir 🌲. Often found near decaying wood 🍂. Grows solitary or in small groups in mixed hardwood-conifer forests along the Pacific Northwest to Central California. Typically fruits in fall and winter ❄️.
🔬 Microscopic Features:
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Spores: 8.5-12 x 6-8 µm, ellipsoid to ovoid, smooth, amyloid.
Basidia: 4-spored, with clamps.
Pileipellis: A cutis of elongated elements (1-9 µm wide).
Lamellar trama: Bilateral, with a branched subhymenium.
🧪 Chemical Reactions: KOH Test: Negative on all surfaces.
👀 Look-Alikes
Several mushrooms resemble Amanita smithiana, and some of them have been linked to similar poisonings! Be extra cautious when identifying:
🔸 Amanita sphaerobulbosa – Another toxic Amanita, reported in similar poisoning cases.
🔸 Amanita proxima (Spain) – Known for toxicity, sometimes confused with edible species.
🔸 Saproamanita thiersii – Similar appearance, but not a true Amanita.
🔸 Amanita silvicola – A close look-alike, but with a marginate, bulbous base and skinnier spores (7–10 x 4–6 µ).
🍂 The Matsutake Mix-Up
Mushroom hunters searching for the prized matsutake (Tricholoma magnivelare) have mistakenly picked Amanita smithiana—a dangerous error! Though they may seem similar at a glance, key differences include:
✔️ Stature – Amanita smithiana is taller; matsutake is stockier.
✔️ Cap Surface – Amanita smithiana has cottony veil remnants (young specimens); matsutake does not.
✔️ Ring (Annulus) – Matsutake has a persistent ring; Amanita smithiana usually lacks one.
✔️ Stem Base – Amanita smithiana has bands of scale-like rings and a root-like extension; matsutake lacks these.
✔️ Odor – Matsutake smells spicy, while Amanita smithiana has a mild scent when young, turning unpleasant with age.
💀 Other Deadly White Amanitas
Several toxic Amanitas in California and the Pacific Northwest resemble Amanita smithiana:
⚠️ Amanita phalloides (Death Cap, white form) – One of the deadliest mushrooms in the world!
⚠️ Amanita ocreata (Destroying Angel) – Another lethal Amanita, often confused when its universal veil sloughs off.
⚠️ Amanita magniverrucata – Has large, anchored pyramidal warts on the cap.
⚠️ Amanita cokeri – Similar to A. magniverrucata but with smaller, persistent tan warts.
Photo sources:
Photo 1-2 - Author: Mandy Hackney (CC BY 4.0)
Photo 3 - Author: Mandy Hackney (CC BY 4.0)
Photo 4 - Author: Alan Rockefeller (CC BY-SA 4.0)
