1. Amanita arocheae, oak (Quercus) forest, Andean Colombia.
Amanita arocheae is a species apparently restricted to Mesoamerica and Andean Colombia. The way pigment is distributed on the cap and the general form of the fruiting body is strongly suggestive of this mushroom's relationship to A. phalloides. In fact, the species is reported to contain deadly Amanita toxins and has been called "A. phalloides" in the past by mycologists in Mexico.
The cap of A. arocheae is 30 - 110 mm wide, rounded conic at first and then convex; it may become flattened and umbonate with further expansion. The cap's color is grayish to umber-brown, and it is streaked with apparent radial fibrils. It tends to be grayest when young and browner at maturity. The margin is not striate. The cap's flesh is white. Volval remnants are almost always absent from the cap.
The gills are free or only very narrowly attached to the top of the stem, close to crowded, thin, and white. Short gills are frequent, with variable length, and are not squarely cut off.
The stem is 80 - 200 × 5 - 17 mm, white (not changing color when cut or bruised), and bears white to pale gray fibrils on its surface. The stem's flesh is white and does not bruise or stain. The stem has a pronounce, nearly spherical bulb at its base; and the volva is notably present as a white membranous flap (or limb) arising from the bulb. A white, skirt-like ring is present at the top of the stem.
The odor is mild to disagreeable. The taste was not reported. Amanita arocheae contains amatoxins and is deadly POISONOUS.
The spores measure (5.8-) 7.2 - 10.0 (-12.8) × (5.3-) 6.8 - 9.5 (-12.0) µm and are globose to subglobose (infrequently broadly ellipsoid) and amyloid. Clamps are not present at bases of basidia.
The species is known from oak (Quercus) forests from central Mexico to Andean Colombia.
from protolog: [210/10/8] (5.8-) 7.0 - 10.0 (-12.8) × (5.5-) 6.8 - 9.5 (-12.0) μm, (L = (7.5-) 8.1 - 9.4 μm; L' = 8.6 μm; W = (7.1-) 7.6 - 8.9 μm; W' = 8.1 μm; Q = 1.0 - 1.11 (-1.27); Q = 1.04 - 1.07 (-1.10); Q' = 1.06), hyaline, colorless, smooth, thin-walled, weakly amyloid to amyloid, globose to subglobose, occasionally broadly ellipsoid, often adaxially flattened; apiculus sublateral, cylindric, sometimes prominent; contents guttulate to granular; color in deposit not recorded.
composite data from all material examined: [312/16/14] (5.8-) 7.2 - 10.0 (-12.8) × (5.3-) 6.8 - 9.5 (-12.0) μm, (L = (7.5-) 8.1 - 9.6 μm; L' = 8.7 μm; W = (7.1-) 7.6 - 8.9 μm; W' = 8.2 μm; Q = 1.0 - 1.12 (-1.27); Q = 1.04 - 1.09 (-1.10); Q' = 1.06), hyaline, colorless, smooth, thin-walled, weakly amyloid to amyloid, often adaxially flattened, globose to subglobose, occasionally broadly ellipsoid; apiculus sublateral, cylindric, sometimes prominent; contents guttulate to granular; white in deposit.
Solitary. Colombia: At 2500 - 2900 m elev. Under Q. humboldti in loamy soil or under Colombobalanus [=Trigonobalanus] excelsa. Costa Rica: At 2350± m elev. In wet dark loam of mixed broad-leaf forest with Q. copeyensis and Q. seemannii. México: At 2150 - 2600 m elev. In mesophytic, montane woods (e.g., Pinus/Quercus forests and forests including Q. crassifolia Humb. & Bonpl., Q. candicans Née, Alnus jorullensis HBK, and Clethra mexicana DC.) in humus.
COLOMBIA: ANTIOQUIA—Mpio. San José de la Montaña - 13± km S of San José de la Montaña along road to Labores, 26.xi.1986 R. E. Halling 5071 (holotype, HUA; isotype, NY). Mpio. Santa Rosa de Osos - vereda “El Quínce,” corregimiento de Aragón, finca “San Bernardo,” 17.vi.1991 A. E. Franco-M. 763 (COL; NY).
VALLE—Mpio. Pance - Parq. Natural Los Farallones, Centro de Educacion Ambiental El Topacio, 30.v.1990 A. E. Franco-M. 507 (paratype, NY).
SAN JOSÉ—Ctn. Dota - Copey de Dota, 12 km S of Copey on rd. to Providencia [9°35’19" N/ 83°53’3" W, 2800 m], 20.x.1994 R. E. Halling, M. Mata & L. Umana [Halling 7395] (NY; USJ); San Gerardo de Dota no. 1, 5± km SW of Cerro de la Muerte, Albergue de Montaña Savegre (Cabinas Chacón) [9°33’2” N/ 83°48’27” W, 2200-2350 m], 11.viii.1993 G. M. Mueller 4581 (F 1110889), 25.vi.1995 R. E. Halling s.n. [Tulloss 6-25-95-A] (RET 155-2; USJ), “Alberto” s.n. [Tulloss 6-25-95-K] (RET 155-3; USJ), 8.vii.1995 A. E. Franco-M. s.n. [G. M. Mueller 5242] (F 1112637). Ctn. Unkn., 5 km NW of Cerro Buenavista, 26.vii.1992 B. A. Strack, L. D. Goméz, G. Hewson & G. M. Mueller [Mueller 4400] (F 1102453).
GUERRERO—Mpio. Chilpancingo de los Bravo - Omiltemi, El Faisal, 11.vii.1985 J. Cifuentes Blanco 2138 (paratype, FCME as “A. phalloides”); Mpio. Chichihualco - km 4.5 between El Carrizal and Atoyac, 16.viii.1980 Sergio Madariaga s.n. (paratype, FCME 1152 as “A. phalloides”).
PUEBLA—Mpio. Teziutlán - cañada de Jalapasquito, desviación a Ixtlahuaca, [ix?.1983?] R. Maria Aroche 517 (paratype, XAL as “A. phalloides”). Mpio. Tezuitlán - cerro Techachaca, 27.viii.1983 R. M. Aroche & M. Xolalpa 315 (paratype, FCME as “A. phalloides”), 28.viii.1983 R. M. Aroche & M. Xolalpa 317 (paratype, FCME as “A. phalloides”), 17.ix.1983 R. M. Aroche & M. Xolalpa 513 (paratype, FCME as “A. phalloides”), [ix?.1983?] R. M. Aroche & J. Bonavides 515 (paratype, FCME as “A. phalloides”).
—R. E. Tulloss
Information to support the viewer in reading the content of "technical" tabs
can be found here.
Tulloss, Ovrebo & Halling
"Latin American Death Cap"
1. Amanita arocheae, oak (Quercus) forest, Andean Colombia.
Dr. Roy E. Halling - (1) from oak (Quercus) forest, Andean Colombia.
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.