Summary:
Subgenus Phalloideae. Amanita phalloides is a deadly poisonous species which is common in California and has become common in recent years in the Pacific Northwest as well. Its features include 1) cap that is green to brownish olive, yellow-green, yellowish or sometimes white, often fading when old, the surface smooth, viscid when moist, often shiny when dry or with a metallic luster, sometimes with one or more thin, silky, white veil patches, the margin not typically striate, 2) close gills that are adnate to adnexed or free, and white to tinged faintly greenish, 3) stem that usually widens downward, white or tinged cap-color, smooth or with scales and fibrils, 4) fragile, superior, skirt-like, membranous ring that is usually persistent, 5) volva that is sac-like, membranous, white, thin and fragile, usually buried and sometimes disintegrating, and 6) odor mild to pungent or nauseating (like raw potatoes or chlorine), (Arora). The greenish coloration is helpful when present as is pungent odor when old. Amanita phalloides can be white overall. The fatal dose varies tremendously but averages 2 ounces. Amatoxins which are resistant to cooking or freezing damage the liver and kidneys. Silibinin, a drug that can be derived from the plant milk thistle, Silybum marianum, is being assessed in amatoxin poisoning cases (along with aggressive hydration) to reduce the effect on the liver.

Cap:
4-16cm across, at first nearly oval then convex to flat; "color variable: green to brownish olive, yellow-green, yellowish, or sometimes white, often darker toward center and paler at margin, often fading when old (to grayish green, light brown, olive-buff, dull yellowish etc.)"; "sometimes with one or more patches of thin, silky, white universal veil tissue", "smooth, viscid or tacky when moist, often shiny when dry or with a metallic luster", margin typically non-striate, (Arora), rarely white, (Lindgren), fuscous, some shade of olive, olive-yellow, greenish, yellowish green or nearly white, at times with a brownish or grayish cast or with blackish streaks, usually darkest in center; "viscid, becoming dry and glistening when old, not hygrophanous, smooth, sometimes with radiating innately fibrillose streaks, glabrous, rarely with one or two large patches of universal veil tissue", (Ammirati(11))

Flesh:
white (Arora), white or yellowish green near cap surface (Ammirati(11))

Gills:
"adnate to adnexed or free, close"; white, or tinged faintly greenish, (Arora), subgills numerous, attenuate, (Lindgren), free or when young attached by a slight decurrent tooth, close to subdistant (several tiers of subgills), broad, white or when old slightly yellowish, unchanging when bruised, (Ammirati(11))

Stem:
5-18cm x 1-3cm, widening downward or equal with an enlarged base, stem solid or hollow; white sometimes tinged with cap color, "smooth or with minute scales and fibrils", (Arora), white with fibrous or scaly ornamentation that is white or colored like cap, (Lindgren), VOLVA universal veil membranous, white, forming sac-like volva that sheathes base of stem, the volva "thin and rather fragile, usually buried in ground and sometimes disintegrating", (Arora)

Veil:
"membranous, white or tinged yellow green", forming a persistent but fragile, superior, skirt-like ring that may disappear when old, (Arora)

Odor:
"at first mild, but later quite pungent or nauseating (like raw potatoes or chlorine)", (Arora), sickening sweet, or like raw potatoes, (Lindgren), sweetish, unpleasant when old, (Breitenbach)

Taste:
not unpleasant, but do not try it: too poisonous

Microscopic spores:
spores 7-12 x 6-9 microns, elliptic to nearly round, smooth, amyloid, (Arora), spores 7.7-10.1 x 6.7-8.5 microns, nearly round to broadly elliptic; basidia 4-spored, 50-62 x 12-15 microns, without basal clamp; pleurocystidia not seen, marginal cells 29-45 x 13-25 microns, pyriform to vesicular; cap cuticle of periclinal hyphae 1.5-6 microns wide, "hyphae in the uppermost layer gelatinized, deeper hyphae brownish-pigmented", septa without clamp connections, (Breitenbach), spores 7-12.8 x 5.5-10.2 microns, but somewhat variable: Tanghe and Simons (1973) reported measurements (6.5)7.4-8.8(9.6) x (5.6)6.1-7.3(9.0) microns; basidia 2-spored or 4-spored, (Ammirati(11))

Spore deposit:
white (Arora)

Notes:
Amanita phalloides is found at least in BC (vouchers at Pacific Forestry Center and University of British Columbia), OR, and CA, (Arora), and WA (Ammirati(11)). New York Botanical Garden has collections from QC, AL, CA, CO, CT, DC, DE, FL, GA, IN, MA, ME, MI, MD, NC, NH, NJ, NY, OH, PA, TN, TX, VA, VT, Uruguay, Czech Republic, France, Germany, Italy, Norway, Sweden, Switzerland, and Australia. Tulloss(6) examined collections from BC, WA, CA, MA, MD, ME, NJ, NY, PA, Argentina, Czech Republic, France, Netherlands, Norway, Switzerland, and Madagascar.