Amanita smithiana

The following is based for the most part on the description by Tulloss and Lindgren (1992).

The cap of A. smithiana is 50 - 170 mm wide, white to whitish or ivory (with tan, pink, and yellowish tones sometimes present after handling or in dry weather), hemispheric to convex to plano-convex, sometimes somewhat umbonate, with a nonsulcate, appendiculate margin.  The flesh is white and unchanging and up to 20 mm thick over the stem.  The cap is covered with floccose-felted remnants of volva forming irregularly shaped, floccose warts in young and floccose-felted patches in older specimens.

The gills are crowded, free to narrowly adnate, white, bruising slowly to buff or pinkish buff when handled, rarely forking, and 6 - 11 mm broad.  The short gills are truncate to subtruncate to rounded truncate to attenuate (the longer ones) and often unevenly distributed among the gills.

The stem is about 60 - 180 × 10 - 35 mm, with floccose-felted remnants of the ring near the top and some vague, felted, wart-like remnants of volva at the base of the stem and the top of the bulb.  The stipe's bulb is apparently always collected only in part—(to our knowledge) never with the basal narrow radical (see background silhouette in above illustration on right) in unbroken condition.  The large recorded dimensions for a bulb with attached radical are 300 × 55 mm, and the radical in this case was clearly broken at the bottom.

The odor can be very unpleasant in age and "truly obnoxious" in senility.  At first it is absent to mild to faintly pungent—described as salty, like dust from Douglas fir bark chips, yeast-like, and like green tomatoes or tomato plants.  Persons poisoned by ingestion of A. smithiana described the taste as turnip-like, sometimes with an acidic or bitter component.

The spores measure (6.5-) 8.8 - 12.0 (-16.0) × (4.3-) 5.8 - 8.0 (-10.8) µm and are amyloid and ellipsoid to elongate (infrequently broadly ellipsoid to subglobose, infrequently cylindric).  Clamps are present at bases of basidia.

This species is confirmed as POISONOUS.  At least one kidney toxin has been identified in Amanita smithiana.  Several cases have been reported in which the kidney or the liver and kidney both ceased to function at least for a time.  One of the great dangers is the accidental collection of A. smithiana by commercial harvesters (or private collectors) of one of the American taxa similar to, and sold as, "matsutake"—Tricholoma magnivelare (Peck) Redhead.  It is important for "matsutake" collectors in western North America to be very familiar with A. smithiana and how to distinguish it from the treasured species they are seeking.  A 2009 case study and a review of relevant toxicological literature can be downloaded here (PDF 1.33 MB).

Poisonings with similar symptomology have been reported for A. nauseosa, A. proxima, A. sphaerobulbosa, and A. thiersii.  All species taxonomically related to these taxa should be considered suspect.

The species was originally described from Oregon and Washington, U.S.A.  The known range now extends from Prov. British Colombia, Canada through the U.S. west of the Great Plains southward to central Mexico. Reports are spotty south of Santa Cruz, California.

The species is associated with alder, Douglas Fir (Pseudotsuga), fir, hemlock (Tsuga), larch, pine, and oak. It is probable that A. smithiana occurs throughout the Douglas Fir/Western Hemlock Zone of the Pacific Northwest (Canada and U.S.).

This species was often called "A. solitaria" by authors treating fungi of the Pacific Northwest states of the U.S.  It is quite distinct from the the European species (A. solitaria (Bull. : Fr.) Fr.).

Bas (1969) placed this species in his stirps Rhopalopus.—R. E. Tulloss and J. E. Lindgren.

The editors of this site owe a great debt to Dr. Cornelis Bas whose famous cigar box files of Amanita nomenclatural information gathered over three or more decades were made available to RET for computerization and make up the lion's share of the nomenclatural information presented on this site.

Paracresol test for tyrosinase - positive except in base of bulb and in lamellae, with strongest reaction in top third of stipe (visible in about 5 min.).  Syringaldazine test for laccase - in mature material positive in line parallel to pileipellis and about 2 mm below it in pileus context (almost immediate reaction, but fading away in 5 - 12 min.), also in spots on lamellae, in central stipe (persisting up to 45 min. or more), and very tip of bulb; in immature material (in varying stages of expansion) positive throughout pileus context above lamellae, in a spot in upper stipe and on partial veil near pileus margin or positive only in lower bulb or infrequently negative throughout basidiome (Sierra Co. collection).  Test vouchers: Lindgren ?, 9722; Tulloss 2-13-98-A.

Results according to Breckon (1968)—on exposed context of the lower stipe and bulb unless otherwise noted: FeSO4 - negative; 3% KOH - negative; Melzer’s reagent - negative; phenol - negative to weakly positive; phenolaniline - negative to weakly positive; tincture of guaiac - slowly and weakly positive. Lindgren (Tulloss & Lindgren, 1994) has generally confirmed these results: FeSO4, 10% KOH, PADAB, 95% ethanol all negative.

This striking mushroom is conspicuous because of its often robust stature, the frequently extensively radicating bulb, and its stark whiteness when young.  As A. smithiana matures, the delicate, floccose, universal veil can be washed off by rain or, in hot, dry weather, change to flat tan warts.  This variation has led to misidentification and much confusion about this species.  Often little or no trace of partial or universal veil is present on mature specimens.  Such specimens may not be recognized by a collector as belonging to Amanita.

There is increasing danger of mistaken identity on the part of ill-informed collectors attracted by the current high prices for “matsutake” and increasing pothunter interest in Tricholoma magnivelare (Peck) Redhead [=Tricholoma ponderosum (Peck) Sing.≡Armillaria ponderosa (Peck) Sacc.].  Amanita smithiana is common in southern British Columbia, Washington, Oregon, and northern California; it occurs, at least occasionally, in southern California, Idaho, and New Mexico.  Particularly because it appears to be poisonous, it should be more widely and completely known.

The literature often ascribes a strong odor to A. smithiana.  It is the impression of Lindgren (who has collected the species frequently) that the presence of a strong odor is associated with the aging or decay of the basidiome.  (Decay is usually noticeable first at the base of the bulb.)  Her field notes indicate that some fresh, sporulating specimens were still odorless four days after collection—even when longitudinally sectioned.  Further, in our examination of many collections made by Drs. C. H. Kauffman (MICH), A. H. Smith (MICH), D. E. Stuntz (WTU), and H. D. Thiers (SFSU) and by the correspondents of Dr. Smith (MICH), we found a number of cases in which the collector noted that the specimens had no odor when fresh.

Spores of immature basidiomes may have an average Q equal to or greater than the average Q seen in mature ones.  The second highest Q noted (1.84) was from Breckon 660 which had very few mature basidia.  It should also be noted that Breckon 660 may be abnormal because of its having been collected near the apparent southern extreme (Santa Cruz Co., Calif.) of what appears to be the main body of the range of A. smithiana.  The highest value of Q noted was from Breckon 221, a depauperate specimen, again from Santa Cruz Co.  The lowest value of Q noted was found in Thiers 38316 the lamellae of which were extensively attacked by a mold.  Because very few collections included spore prints, only spores on lamellae were measured for the sake of consistency.  In all cases, a portion from the mid-region of a lamella was used.

It is noteworthy that the two collections made at considerable distance from all the others (Santa Barbara Co., Calif., and New Mexico collections) were collected after rain and had spores with Q of 1.56 and 1.41 respectively.  Specimens of the Santa Barbara Co. collection are somewhat to very contorted, and one seems to lack lamellae under part of the pileus.

We ran across a small number of collections of A. silvicola misdetermined as A. smithiana.  We find that macrochemical spot tests can be used to distinguish the two taxa.  Phenoloxidase spot tests were carried out by Lindgren on Lindgren 91-50, on an additional collection of A. smithiana, and on three collections of A. silvicola.  The reactions reported above for A. smithiana were seen in both tests of that species.  The response in all tests of A. silvicola (for both laccase and tyrosinase) was negative.  Since paracresol and syringaldazine are easily carried into the field, the application of either reagent to a longitudinal section of a basidiome provides a quick chemical test that will distinguish between these two white taxa.  In the laboratory, the lack of basidial clamps, the lack of chains of inflated cells in the universal veil remnants left on the pileus, and smaller spores with higher Q aid in distinguishing A. silvicola from A. smithiana (Bas, 1969).

A question has been raised as to whether it is correct to identify the toxin in this species with allenic norleucine and similar compounds (Kirchmair et al., 2012).  The ability to detect the kidney toxin or toxins in this species and in soup prepared from it has been reported recently (Apperley et al., 2013).  Clearly the substance thought to be the primary toxin in A. smithiana is not broken down by heat—it survives boiling.  In addition, the substance does not deteriorate with age in herbarium specimens (I. Garber, pers. comm.).

[ Section Lepidella page. ]  [ Amanita Studies home. ]  [ Keys & Checklists ]
[ Pacific coastal states (USA) & region list ]

[ Section Lepidella page. ]  [ Amanita Studies home. ]  [ Keys & Checklists ]
[ Pacific coastal states (USA) & region list ]