Amanita virginiana

Amanita virginiana is often so small that it can be found in good condition in lawns around mature oaks after the lawn has been mowed.

Its 7 - 50 mm wide cap is dark brown at first and takes on grayer tones in expanding; its margin is striate from one-third to one-half of its radius and more pallid than its center.

The gills are free or nearly so, rather close, white to off-white; and short gills are truncate to subtruncate.

The bulbless stem is 8 - 76 × 2 - 7 mm with a small white volval sac (up to 14 mm high) at its base that some times looks like a small exploded piece of popcorn and with a fragile tiny annulus that is very often lost at maturity.

The spores measure (9.1-) 11.5 - 15.0 (-20.5) × (6.5-) 8.5 - 11.2 (-15.5) µm and are broadly ellipsoid to ellipsoid (rarely subglobose or elongate) and inamyloid.  Clamps are common at bases of basidia.

This is species is one of the small amanitas that has rather plentiful 2-spored basidia and spores that are quite large for the genus. Amanita pachysperma G. F. Atk. and A. subvirginiana (Murrill) Murrill appear to be closely related taxa.  One should also compare A. ristichii Tulloss.

Amanita virginiana is associated with oak (Quercus) in the eastern U.S.A.  It is often plentiful locally, but apparently is seldom (knowingly) collected.—R. E. Tulloss

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.

Amanita virginiana is a small to very small mushroom with brownish gray to dark brown to gray-brown to fuligineous disc and pallid pileus margin.  Its white stipe is decorated by a superior to median to subinferior, white partial veil that is usually persistent.  The universal veil is found as a sheathing volva or as warts on the pileus and, in the latter case, a set of small splayed limbs on the stipe base suggesting a kernel of popped corn.  The species appears to be associated with Quercus and Fagus.

Inflation of the short hyphal segments of the subhymenium was not seen in all specimens and was usually seen only locally in those specimens in which it occurred.  I have the impression that inflation of such cells is more common in A. pachysperma.  For further comparison of A. virginiana to the other similar taxa, see the discussion sections following descriptions of A. pachysperma, A. ristichii, and A. subvirginiana.

Coker (1917) equated A. spreta var. parva with A. virginiana [for which he reports the spore measurements of 11 - 13 × 7.5 - 10.5 µm (est. Q’ = 1.36)].  Coker determined as A. spreta var. parva his collection Coker 1624 (NCU? n.v.) for which he gives the spore dimensions as 10 - 12.6 × 6.7 - 8.2 µm (Q’ = 1.53).  These spores are considerably narrower than those of A. virginiana. The spores of A. spreta var. parva as described by Beardslee are very nearly the size given by Coker [10 - 12 × 7 - 8 µm (est. Q’ = 1.47)]—smaller than those measured for any of the other taxa cited above.  As a consequence, it seems unwise to accept Coker’s proposal of synonymy of A. spreta var. parva with A. virginiana without further evidence.  Coker 1624 could not be located in NCU.  A packet in NCU marked "Amanita spreta var. parva ex type" proved to contain a small box marked in black ink "Venenarius virginianus Part of type" in what appears to be W. A. Murrill’s hand; the material inside was indeed A. virginiana.

Coker’s description of A. spreta var. parva reads "This is an extremely little form of A. spreta and is a small plant with a very pale cap, and veil not smoky.  Cap 3.5 cm. broad, pale buff in center, fading to nearly white on margin which is strongly striate.  Gills attached, about 3 mm. deep, white.  Stem 13 cm. long, 6 mm. thick, finely fibrillose below the veil, minutely granular above; a distinct central cylinder that is lightly stuffed.  Veil a small collapsed ring 2 cm. from the cap, white.  Volva long, narrow, attached to the very base of the stem, which is not bulbous.  Spores elliptic, 6.7-8.2 × 10-12.6 µ." Note that the stipe length does not match that of any of the small North American species with numerous bisterigmate basidia, and the cap color is more like that of A. subvirginiana than that of A. virginiana.

I could find no evidence that a type of A. spreta var. parva exists or has ever existed; and I could find no authentic material of the taxon.  There is no authentic material of A. spreta var. parva in MICH (in which Beardslee’s herbarium is now included).  In Beardslee’s files (preserved at MICH), there is no file for A. spreta var. parva; nor is mention of this taxon made in Beardslee’s file on A. spreta (Peck) Sacc. (examined by me).  Moreover, it seems very unlikely that, if a type of A. spreta var. parva were known to Coker, he would have designated what he considered to be the type of a synonym (A. virginiana) as the type of A. spreta var. parva in his herbarium.  Since the Beardslee taxon is poorly described and apparently lacks a type, it must be considered to be of questionable taxonomic value at present.  It is listed under nomina dubia in (Tulloss 1993).  If it can be defined clearly in the future and, moreover, is then establsihed as a variety of A. spreta, its basidia would be expected to be dominantly 4-sterigmate.

In NY, I found a packet (W. A. Murrill 179) with label indicating that it was a topotype of V. virginianus collected during the same period as was the holotype.  Murrill must never have checked the spores of this collection, which is clearly not conspecific with the holotype.  As noted by L. R. Hesler (annotation slip attached to packet of Murrill 179), the spores of the single specimen in the packet are globose to subglobose.

The Washington Crossing St. Pk. (New Jersey) collections were made in a lawn that was frequently mowed.  The specimens were short enough to survive the mowings intact.  Since seven collections were made at this site in a period of five days (1-5 July 1984) and since it is possible that they represent fruiting of a single mycelium, it is of interest to see the amount of variation in spore size and shape measured on the specimens of these collections:

[380/19/7] (9.1-) 11.5 - 14.5 (-16.2) × (6.5-) 8.8 - 11.5 (-13.0) µm, (L = (12.3-) 12.5 - 13.6 (-13.7) µm; L’ = 13.0 µm; W = (9.5-) 9.6 - 10.7 (-10.9) µm; W’ = 10.1 µm; Q = (1.07-) 1.12 - 1.48 (-1.76); Q = (1.16-) 1.19 - 1.38 (-1.39); Q’ = 1.30).

An isolate from Began 388 provided the basis for cultural studies reported in (Began, 1988).

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[ Keys & Checklists ]
[ Draft description of, & key to, sect. Caesareae ]
[ Great Smoky Mtns. N.P. & region list ]
[ New Jersey & region list ]