Amanita subvirginiana

The cap of A. subvirginiana is about 20 mm wide, convex to plane, without an umbo, somewhat viscid, with a striate margin (50% of the radius).  The cap is uniformly avellaneous.  The flesh is white and very thin.  Volval remnants are absent.

The gills are adnexed, subdistant to subcrowded, white, neither very broad nor very thin, and slightly ventricose.

The stem is about 40 × 3.5 - 4 mm, milk white, narrowing upward, dry, smooth, and hollow.  The saccate volva is white, narrow, and lobed.

The spores measure (9.0-) 10.2 - 14.0 (-15.5) × (6.2-) 7.8 - 10.2 (-11.8) µm and are broadly ellipsoid to ellipsoid and inamyloid.  Clamps are large and common at the bases of basidia.

Amanita subvirginiana was originally described from Florida (USA). It occurs in hammock vegetation (a term peculiar to Florida and indicating usually mesic, climax vegetation—hardwood forest including Oak and Magnolia, etc.).

This species is represented in collections only by the type, so far as I know. Similar taxa are listed in the discussion of A. virginiana (Murrill) Murrill.—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.

This species is only known from Alachua Co., Florida, U.S.A.

As of RET's revision of it in 1992 (Tulloss 1993), the single specimen of the holotype was in only moderately good condition and very fragile.  The stipe was broken just below the annulus, and about a quarter of the pileus remained tenuously connected to the top of the stipe.  The tissues of the hymenium, subhymenium, and lamella trama were fragile, possibly partially deteriorated, and not very strongly congophilous; this situation made examination rather difficult.  For example, despite the fact that clamps are large and plentiful at the base of the basidia, they are so faint (even at 1000×) that one must search for them diligently.

The current taxon is very similar anatomically to A. virginiana and, consequently, differs from A. pachysperma.  Amanita subvirginiana differs from A. virginiana in pileus color, thickness of the pileipellis, frequency of 4-sterigmate basidia, the size and frequency of vascular hyphae in the lamella trama, the occurrence of spores with slightly thickened walls, and (N.B.: the sample is small) in spore size.  Considering the condition of the holotype of A. subvirginiana and the fact that the two specimens of Thiers 4790 were dried at the very outset of sporulation, it seems prudent to wait until fresh material can be collected before drawing a final conclusion about the present taxon's taxonomic relationship to A. virginiana.

Singer (1951) equated "A. spreta var. minor Beardslee" [probably intending, "A. spreta var. parva Beardslee"] with A. subvirginiana.  The Beardslee taxon has an extremely limited protolog and is of dubious taxonomic value at present.  For more details concerning A. spreta var. parva, see the discussion under A. virginiana.

Murrill interprets something in the hymenium of the present species as large, clavate cystidia of which he says, "inflated, obtuse, thin-walled, hyaline, scanty, projecting about 20 µ."  I saw nothing that could be interpreted as a cystidium.  An occasional basidium will project up to 10 µm or so beyond the rest of the hymenium; this is quite common in Amanita.

Amanita - Pine wds 7-7-38 solitary/ Sl viscid 2 cm, nearly white + sl smoky disk, marg striate/ gs + ridge to st. ring median[.] volva limb [drawing of small subtriangular limb] to [illegible][.] bulb small/ Small form of A. gemmata/ Cf. subvirginiana

[spore drawing with one guttule] 10-11 × 6-7/ sm/ subovoid 1-gut

subovoid/ = 10-12 × 8-9

cf. subvirginiana but color dif + spores too narrow - Habitat very dif

Thiers 4790 apparently represents the same entity as Murrill F17496.  It differs from the holotype of A. subvirginiana only in pileus coloration.  It is interesting to note that the dried pilei of Thiers 4790 are between 5YR 7/4 and 7.5YR 6/6 while the the Munsell code for Ridgway’s Avellaneous is 10YR 7/3 (slightly less orange than the exsiccata of Thiers 4790).  This suggests that the holotype may have been slightly drying when collected.  New collections of similar material (very pallid pileus and otherwise like A. subvirginiana) would be very useful in understanding the present species; and new material is badly needed to supplement the holotype collection.

Two other collections in FLAS labeled "A. subvirginiana" proved not to belong to either sect. Caesareae nor sect. Vaginatae.  Apparently the present species is quite rare.

My findings are an extension of those of Jenkins (1979).  The present taxon is omitted by Jenkins (1986) in his survey of Amanita in North America.