1. Amanita fallax, La Malintzi Volcano, Tlaxcala edo., Mexico.
The cap of Amanita fallax is 30 to 110 mm wide, hemispheric at first to broadly concave to plano-convex, white, becoming pale vinaceous and then cinnamon-brown in age, tacky to moderately viscid when wet, with a nonstriate (or slightly striate in age) margin. The volva is present as one or a few large patches, white to grayish yellow to pale brown vinaceous. The flesh is white, firm, staining pink or rosy vinaceous or brownish-rose when cut, often rapidly fading, but then brownish in old cuts.
The gills are narrowly attached, somewhat sinuate, close, white to pale orangish white, bruising pink then changing to
brown, moderately broad, with white minutely fimbriate edges that become brown with age. The short gills are truncate to subtruncate.
The stem is 30 - 135 × 8 - 34 mm, white, becoming cinnamon brown in age, cylindric, decorated with fine, white to brown appressed flocculence especially in upper quarter, fibrillose below, exannulate or with evanescent submembranous subapical to superior, yellowish-white ring. The base is rounded. The saccate volva is whitish and cylindrical. The flesh is hollow to stuffed.
The odor of this mushroom is slightly fragrant to fungoid to ammonia-like. Taste is mild at first, but then becomes bitter and/or soapy.
The spores measure (7.2-) 9.4 - 14.5 (-20.8) × (4.9-) 5.6 - 8.0 (-12.2) µm and are ellipsoid to elongate to cylindrical and amyloid. Clamps are probably not present at bases of basidia.
—R. E. Tulloss
Tulloss & G. Wright
fallax, "deceitful" or "false" Because of this entity's being commonly confused with diverse species of section Amidella.
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Olive text indicates a specimen that has not been
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The following material is based on original research by R. E. Tulloss.
[253/13/3] (7.7-) 9.8 - 14.0 (-20.8) × (4.9-) 5.6 - 7.0 (-9.0) μm, (L = 10.7 - 12.8 (-13.2) μm; L' = 11.6 μm; W = 6.0 - 6.7 (-6.9) μm; W' = 6.3 μm; Q = (1.40-) 1.50 - 2.27 (-2.75); Q = 1.67-2.07 (-2.12); Q' = 1.85), hyaline, colorless, smooth, thin-walled, amyloid, ellipsoid to elongate to cylindric, occasionally expanded at one end, very rarely constricted; apiculus sublateral to subapical(?), cylindric; contents guttulate; ?? in deposit.
Subgregarious. California: At ca. 610 m elev. In open area along rd. on sandy soil ca. Quercus agrifolia. Baja California N.: Under Q. agrifolia.
BAJA CALIFORNIA NORTE—Santa Rosa, carrera Tijuana a Ensenada, 25.iii.1992 Tones, Molina & Lizarraga 286 (BCMEX).
CALIFORNIA—Riverside Co. - Santa Ana Mtns., El Cariso, 22.iii.1982 David Hayward s.n. [Greg Wright 2961] (RET 002-4; in herb. G. Wright), s.d. Paul & Mary Harding s.n. [G. Wright 2961A] (RET 669-1).
Each spore data set is intended to comprise a set of measurements from a single specimen made by a single observer;
and explanations prepared for this site talk about specimen-observer pairs associated with each data set.
Combining more data into a single data set is non-optimal because it obscures observer differences
(which may be valuable for instructional purposes, for example) and may obscure instances in which
a single collection inadvertently contains a mixture of taxa.