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.
The following text may make multiple use of each data field.
The field may contain magenta text presenting data from a type study
and/or revision of other original material cited in the protolog of the present taxon.
Macroscopic descriptions in magenta are a combination of data from the protolog and
additional observations made on the exiccata during revision of the cited original
The same field may also contain black text, which is data from a revision of the present
taxon (including non-type material and/or material not cited in the protolog).
Paragraphs of black text will be labeled if further subdivision of
this text is appropriate.
Olive text indicates a specimen that has not been
thoroughly examined (for example, for microscopic details) and marks other places in the text
where data is missing or uncertain.
The following material not directly from the protolog of the present taxon and not cited as the work of another researcher is based on original research by R. E. Tulloss.
Amanita subvirginiana is a very small mushroom with a whitish to avellaneous pileus having a long striate margin, with a concolorous or slightly darker umbo; its stipe is white and decorated with a small, submedian annulus and a saccate volva. The following macroscopic description is based on the protolog, Murrill’s notes deposited with the holotype, and original research by R. E. Tulloss.
20± mm wide, uniformly avellaneous or whitish, slightly darker over disc, convex to plane, sometimes umbonate, somewhat viscid; context white, very thin; margin concolorous, striate (0.5R), entire; universal veil absent.
adnexed, subdistant to subcrowded, white, dark brown in exsiccatum, entire, neither very broad nor very thin, not forked, slightly ventricose; lamellulae not described by Murrill.
20 - 40 × 3.5 - 4 mm, milk-white, narrowing upward, dry, smooth, minutely pubescent (lens); context color not recorded, hollow in exsiccatum; partial veil white, unchanging when cut or bruised, subsuperior to median, fixed, small, membranous, simple, persistent; universal veil as saccate volva, white, narrow, lobed, with free limb.
Odorless. Taste not recorded. Edibility unknown.
40 - 45 µm thick [Information on supra- and subpellis is required.]; filamentous, undifferentiated hyphae 2.0 - 4.5 µm wide, densely interwoven, subradially arranged, slightly gelatinized; vascular hyphae not observed; clamps common.
filamentous, undifferentiated hyphae 2.0 - 10.0 µm wide, plentiful, often in loosely interweaving fascicles; acrophysalides subfusiform to fusiform to clavate to broadly clavate to ellipsoid, up to 90 × 44 µm, dominant, thin-walled; vascular hyphae not observed.
bilateral, angle of divergence dominantly very shallow to not diverging, but also (occasionally) up to nearly 45°; wcs = 30 - 40 µm; filamentous, undifferentiated hyphae 1.0 - 8.0 µm wide, thin-walled, densely interwoven, branching; inflated cells sparse, obscured by hyphae, thin-walled, broadly clavate to clavate to narrowly clavate to subfusiform, up to 66 × 27 µm, aligned with hyphae of central stratum or diverging with hyphae that give rise to subhymenium, sometimes with apex reaching bases of basidia; vascular hyphae 2.2 - 11.0 µm wide, branching, sinuous.
wst-near = 35± µm; wst-far = 55± µm; largely composed of branching hyphae at a very shallow angle to the central stratum, with small cells up to three to four deep below the basidia in some regions (up to 16.0 × 11.0 µm, most three-quarters of this size or less), with filamentous, undifferentiated hyphae running subparallel to the central stratum interwoven at basidia bases; basidia mostly arising from uninflated (sometimes quite long) hyphal segments, but occasionally arise from the side of small ellipsoid cells (up to 13.5 × 8.2 µm) that are terminal on such hyphae.
Because of the orientation reported for the hyphae in the subhymenium, RET is suspicious that the tissues of the sole available collection did not rehydrate well. Revision of fresh material is highly desirable.
30 - 50± × 9.0 - 12.2 µm (but few in condition to be measured in holotype), thin-walled, fragile, probably dominantly 4-sterigmate, but also often (about one-third or more) 2-, and occasionally 1-sterigmate; sterigmata up to 9.5 × 3.5 µm; clamps and proliferated clamps large and common (difficult to see in holotype because of poor condition of tissue).
On pileus: absent. At stipe base, exterior surface: comprising widely spaced, longitudinally oriented, rather extensively gelatinized, rather thick fascicles of hyphae between which can be seen the inflated cells, etc. of the interior; filamentous, undifferentiated hyphae 1.5 - 8.0 µm wide; vascular hyphae not distinguishable due to gelatinization. At stipe base, interior: filamentous, undifferentiated hyphae 1.5 - 15.0 µm wide, branching, plentiful, loosely interwoven around inflated cells singly or in fascicles, occasionally having refractive material deposited unevenly (up to slightly more than 1.0 µm thick) on interior walls, with some of larger diameter having slightly thickened walls (less than 0.5 µm thick); inflated cells terminal, single, dominating, subglobose to broadly ellipsoid (up to 65 × 57 µm), subfusiform to clavate to narrowly clavate (up to 135 × 42 µm), thin-walled or with walls slightly thickened (up to 0.5 µm thick); vascular hyphae 2.8± µm wide, very scarce; clamps plentiful. At stipe base, inner surface: gelatinized, otherwise like the interior.
longitudinally acrophysalidic; filamentous, undifferentiated hyphae 2.5 - 9.5 µm wide, branching, plentiful, dominating near surfaces; acrophysalides thin-walled, plentiful, dominating away from surfaces, up to 156 × 37 µm, base often broadly rounded, basal septum sometimes eccentric; vascular hyphae 2.8 - 15.0 µm wide, relatively common away from surfaces.
almost completely gelatinized in holotype; with surface having irregularly scattered pits (evidently due to loss of inflated cells) up to 69 × 48 µm; filamentous, undifferentiated hyphae 1.5 - 4.5 µm wide, with some subradially oriented and others co-parallel and perpendicular to those of the first group; inflated cells not observed within the tissue; vascular hyphae not observed.
from type study of Jenkins (1979): [-/-/1]
10.2 - 11.7 (-12.5) × 7.8 - 9.4 μm, (Q = 1.24 - 1.43; Q' = 1.35),
hyaline, thin-walled, nonamyloid, broadly ellipsoid to ellipsoid, often adaxially flattened; apiculus sublateral, cylindric; contents guttulate;
color in deposit not recorded.
from type study of Tulloss (1993):
[40/1/1] (9.0-) 10.2 - 14.0 (-15.5) × (6.2-) 7.8 - 10.2 (-11.8) μm, (L = 11.7 μm; W = 8.7 μm; Q = (1.22-) 1.25 - 1.47 (-1.54); Q = 1.35).
composite of all material examined by RET: [80/3/2] (9.0-) 10.5 - 13.8 (-15.5) × (6.2-) 7.8 - 10.0 (-11.8) µm, (L = 11.6 - 11.9 µm; L’ = 11.7 µm; W = 8.7 - 8.8 µm; W’ = 8.7 µm; Q = (1.20-) 1.23 - 1.51 (-1.92); Q = 1.33 - 1.37; Q’ = 1.35), hyaline, colorless, smooth, thin-walled or occasionally with walls slightly thickened (0.5 µm or less thick) and then somewhat opaque, inamyloid, congophilous, broadly ellipsoid to ellipsoid, adaxially flattened; apiculus sublateral, rather small, cylindric to truncate-conic; contents granular to multiguttulate (although no visible contents in most spores of holotype); color in deposit unknown.
Solitary to subgregarious. In low humus of hammock (a term peculiar to Florida and indicating usually mesic, climax vegetation—hardwood forest including Quercus, Magnolia, etc.—often slightly elevated compared to surrounding, wetter terrain) or in deep sandy humus of mixed forest of Pinus and hardwoods.
from type study of Jenkins (1979):
U. S. A.: FLORIDA— Alachua Co. - Gainesville,
27.iii.1938 W. A. Murrill F 16134 (holotype, FLAS).
U.S.A.: FLORIDA—Alachua Co. - ca. 5 km SE of current (1992) city line of Gainesville, Prairie Creek Hammock, 27.iii.1938 W. A. Murrill F16134 (holotype, FLAS); ca. 13 km E of Gainesville, Rochelle Hammock, 24.vii.1958 H. D. Thiers 4790 (SFSU).
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.
W. A. Murrill F17496 (FLAS), collected in pine woods in Gainesville, is labeled A. subvirginiana and was determined by Murrill. According to one of the notes in the packet, Murrill found the spores to be 10 - 12 × 6 - 9 µm. According to R. Singer’s notes (F), he examined this specimen and confirmed the determination. There is presently no pileus in the packet. The stipe and volva in the packet are of the same size and form as those of the holotype specimen. Murrill’s notes in the packet read as follows:
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.
—R. E. Tulloss
Information to support the viewer in reading the content of "technical" tabs
can be found here.
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.