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Key to Species of
AMANITA Section PHALLOIDEAE
from North and Central America

Rodham E. Tulloss and Lindsay Possiel
P. O. Box 57, Roosevelt, New Jersey 08555-0057, U.S.A.

Extensive REVISION of this key was completed 16 July 2005.

[Note: Species with pinkish or brick- colored bruising reactions should be referred to Amanita section Amidella.
In the case of a specimen referred to this key that has a strong raspberry red staining reaction and (sometimes) the odor
of anise, it should be referred to A. mutabilis Beardslee in Amanita section Lepidella.

 

1. Spores with Q > 1.7—elongate to cylindric to bacilliform.
  2. Entire basidiocarp white.
    3. Stipe gracile, often largely below surface of soil; pileus at least sometimes appendiculate; bulb often pointed below and usually radicating; spores cylindric to bacilliform; known from sandy Atlantic coastal plain north to at least New Jersey and from the coastal plain of the Gulf of Mexico.

Diverse species of Amanita subsection Limbatulae Bas [sect. Lepidella].

 

    3. Stipe usually mostly above ground, with bulb rounded below (probably a single species); pileus not appendiculate; odor of carrion or chloride of lime; spores (9.5-) 10.2 - 13.8 (-16.0) (3.8-) 4.2 - 5.8 (-6.5) m, with Q = 2.25 - 2.54 (-2.76); described from Florida; known as far north as the coastal plain of North Carolina and as far west as the sandy oak-pine forests of eastern Texas.

Amanita virosiformis (Murrill) Murrill
=Amanita tenuifolia (Murrill) Murrill.

 

  2. Pileus not white; Q <2.5; universal veil with relatively long, upstanding free limb attached only near very bottom of stipe; bulb may be minimal.
    4. Pileus sometimes yellowish cream at first, eventually grayish brown to umbrinous; KOH on pileus orange to reddish orange; spores (10.0-) 10.5 - 12.8 (-14.8) (4.2-) 5.0 - 6.5 (-7.2) m, with Q = 2.0 - 2.28; described from North Carolina and central Mexico.

Amanita longitibiale Tulloss, Prez-Silva & T. Herrera.

 

    4. Pileus black or “midnight blue”  at first, becoming grayer with maturation; spores (8.0-)8.5 - 13.5 (-15.5) (5.0-) 5.2 - 6.5 (-8.5) m, with Q = 1.54 - 1.89; known from the Appalachian Mtns. in North and South Carolina and West Virginia.

Amanita sp. S9 [Tulloss].

Note: Please contact me if you find this fellow!

 

1. Spores with Q < 1.7
  5. Pileus distinctly pigmented, not white, often virgate.
    6. Pileus greenish or olivaceous, sometimes with yellow tint; infrequently white; spores (7.5-) 8.0 - 10.1 (-12.5) (5.5-) 6.1 - 8.0 (-9.0) m, with Q = 1.20 - 1.33 (-1.40); widely introduced and, hence, possible throughout area of interest with various imported trees, Castanea dentata, Pinus, and Quercus, now well-established with indigenous Quercus or Pinus at many localities.

Amanita phalloides (Fr. : Fr.) Link.

 

  6. Pileus grayish to brownish, lacking green, olivaceous, and yellow tints; spores (5.8-) 7.0 - 10.0 (-12.8) (5.5-) 6.8 - 9.5 (-12.0) m, with Q = 1.04 - 1.08 (-1.10); associated with indigenous Quercus spp. from Mexico to Colombia.

Amanita arocheae Tulloss, Ovrebo & Halling.

 

  5. Basidiocarp entirely white, at least at first; pileus not notably virgate.
    7. Basidia dominantly bisterigmate, at least commonly so in late spring and early summer, later in year sometimes dominantly or entirely 4-sterigmate; small to medium-sized mushroom; pileus may take on pale pink, pale orange, or other tints over disc with age; yellow reaction rapidly in response to KOH solution.; spores (5.2-) 7.2 - 9.9 (-11.0) (4.8-) 6.4 - 8.5 (-10.0) m, with Q = (1.05-) 1.06 - 1.18 (-1.20).

Amanita bisporigera G. F. Atk.
= Amanita phalloides var. striatula Peck
= Amanita vernella (Murrill) Murrill.

Note: At least one entity that appears nearly identical to A. bisporigera, but differs in failing to react to KOH or reacting only very weakly has been found repeatedly in the Chiricahua Mtns. of Arizona (USA) and in the neovolcanic zone of central Mexico.  The typically reacting A. bisporigera is not known from Arizona.  The taxonomic status of the nonreacting entity (which has never been described in detail)  is undecided. 

 

    7. Basidia dominantly or entirely 4-sterigmate.
      8. KOH solution producing yellow reaction.
        9. Spores with Q > 1.25 
          10. Partial veil white, membranous and quite thin; bulb often rounded below but sometimes subradicating; universal veil sometimes having very distinct limbus internus; inflated cells in context and universal veil with walls thin or up to 0.5 m thick; spores (6.8-) 8.8 - 12.0 (-13.8) (5.9-) 6.3 - 8.5 (-10.8) m, with Q = 1.27 - 1.47 (-1.52); known from Washington to California, USA, and Baja California, Mexico, with Corylus, Pinus, and Quercus.

Amanita ocreata Peck
= Amanita bivolvata Peck.

Note: A single collection (at the moment, simply called Amanita sp. M35) from the state of Tlaxcala, Mexico, might be keyed out to this terminus of the present key.  The known morphological differences with A. ocreata include the shape of the spores (proportionately narrower, (9.8-) 11.4 - 13.7 (-14.0) (6.8-) 6.9 - 8.5 (-(9.0) m, with Q = 1.66).  Since the field notes on A. sp. M35 when fresh indicate that there was an odor of cheese, it is possible that a hyphomycete was infecting the basidiocarp (see A. polypyramis (Berk. & Curt.) Sacc.); and, since the flesh reportedly stained yellowish, there may have been a second parasite present (see A. subsolitaria (Murrill) Murrill).  This could have distorted both the shape of the fruiting body and the shape and size of the spores. 
T
he single known specimen was sampled for sequencing of the 5 end of the 28S ribosomal RNA gene.  In the subsequent analysis, Amanita sp. M35  proved basal to a clade including A. ocreata, but apparently was distinct from that species (Hallen et al., to appear).

 

          10. Partial veil cream or pale yellowish, membranous, but distinctly thickened; bulb always pointed below; limbate volva upstanding with notable space separating it from the stipe.  Spores (8.5-) 8.8 - 12.0 (-14,4) (5.8-) 6.1 - 8.1 (-9.0), with Q = 1.39 - 1.57; found very infrequently, known from southeastern Canada and northern tier states of the USA (e.g., Michigan and Minnesota) east of the Rockies with Quercus, Tsuga, Pinus, Larix, or Populus; similar in overall macroscopic appearance to A. magnivelaris Peck (below), which doesn't turn yellow with KOH.  The present taxon appears to be rather rare.

Amanita decipiens sensu Lamoureux.

 

        9. Spores with Q <1.20. [Possibly the distinguishing of two taxa here is incorrect.]
          11. Medium to large mushroom; spores (7.0-) 7.5 - 10.0 (-13.2) (6.0-) 7.0 - 9.5 (-11.5) m, with Q = 1.06 - 1.11 (-1.13); name commonly used in eastern USA and southeastern Canada.  See A. bisporigera, above.

Amanita virosa sensu auct. amer.

Note: A. virosa sensu auct. amer. is simply (or, to be more conservative, nearly entirely) composed of 4-spored collections of A. bisporigera. There seems to be a tendency to shift progressively from 2-spored to 4-spored basidia as the fruiting season progresses.  Molecular work (Hallen et al., to appear) has indicated that at least one collection from North America (Virginia, USA)  has been found that falls in a distinct clade with specimens of European A. virosa Lam.  This raises the possibility (among others) that the European species has been recently imported into the US.  Not enough is known of the European species and A. bisporigera so that a complete morphological comparison between the two can be made.  They are separable molecularly.
Spores from northern European collections determined as A. virosa sensu stricto do not differ significantly from those of the 4-spored collections of A. bisporigera.  Spores of the European material measu
re: (6.6-) 8.2 - 10.5 (-13.0) (6.1-) 6.9 - 9.5 (-12.6) m, with Q = 1.06 - 1.10.  Hence, no rapid morphological determination method is known that successfully separates dried collections of unknown origin by region.

 

          11. Small mushroom; spores (4.9-) 8.0 - 10.1 (-11.2) (4.2-) 7.0 - 8.7 (-9.4) m, with Q = (1.09-) 1.16 - 1.17.  Known to the author from the New Jersey Pine Barrens (Pinus-Quercus forest) from late in the collecting season.  Possibly based on depauperate material of the above.

Amanita sp. 33.

 

      8. KOH solution not producing a yellow reaction on pileus or reaction with KOH unknown; spores with average Q > or = 1.20.
        12. Having strong odor of garlic; spores (7.2-) 7.5 - 9.5 (-9.8) 6.5 - 8.0 (-8.2) mm, Q = 1.20 -1.23; described from Florida; occurring with Quercus and Pinus.

Amanita suballiacea (Murrill) Murrill.

 

        12. Lacking garlic odor.
          13. Spores with Q < or = 1.30.
            14. Spores per Marchand (1971) “(8.75-) 10.0 - 10.5 (-11.2) (7.0-) 7.5 - 8.25 (-9.4) m,” with Q approx. 1.2 - 1.3.  See also, A. decipiens sensu Lamoureux, above.

Amanita verna (Bull. : Fr.) Lam.
[Not confirmed from region of study and not known to be distinct from A. decipiens (Trimbach) Andary & Bon.]

[Note: It is currently argued in European literature that the common conception of A. verna as a species that does not turn yellow in KOH may be due to the application of the name to specimens of A. phalloides f. alba (see below). It is noteworthy that my data from white specimens of A. phalloides from the northwestern U.S.A. matches very closely with that provided by Marchand (above). Authors holding this position believe that taxa recently treated as varieties of A. verna that stain yellow with KOH are actually representative of the type variety of A. verna.]

 

            14. Inflated cells in context and universal veil often with walls up to 1.3 m thick; spores (7.5-) 7.8 - 10.8 (-12.0) 6.0 - 8.0 (-10.8) m, with Q = 1.23 - 1.29; possible throughout area of interest with various imported nut trees, Castanea dentata, Pinus, and Quercus.

Amanita phalloides f. alba Britzelm.

[Note: Vittadini’s phrase “totus albus” is not a name, but a descriptive phrase; and Vittadini cannot be held to be the original author of “Agaricus virosus var. albus.” In fact, there is no such name; Vittadini’s taxon is “Agaricus virosus var. b.” Vesel (1934) did not treat this entity as completely white. He states that when Amanita phalloides is completely white, it is properly referred to A. verna or, as he called it, A. phalloides subsp. verna.  RET thinks that white specimens of A. phalloides probably do not deserve separate taxonomic treatment.  See A. phalloides, above.]

 

          13. Spores with Q > 1.30.
            15. Partial veil proportionately large and distinctly thickened.  Spores: (7.2-) 8.2 - 10.8 (-12.5)  (5.2-) 5.8 - 7.8 (-9.2) m, with Q = 1.38 - 1.49; described from New York State, USA; known from as far north as Prov. Qubec.  Apparently, often confused with taxa having thin partial veils.

Amanita magnivelaris Peck.

Note: Yves Lamoureux and RET have gone over his material and discussed it repeatedly over several years.  They now believe that the yellow-staining entity is a relatively rare thing and is (at least) not the normal form of A. magnivelaris.  Temporarily, they call it A. decipiens sensu Lamoureux, above.

 

            15. Partial veil of various diameters and thin.
16. Pileus white, often with (or developing) smoke gray tint; universal veil with plentiful inflated cells; spores often dominantly elongate, (7.0-) 8.0 - 11.0 (-12.0) (4.8-) 5.2 - 6.5 (-7.5) m, with Q = 1.50 - 1.66; originally described from Honduras and Belize in association with Pine (Pinus).

Amanita eburnea Tulloss

 

16. Pileus never having gray tint; universal veil lacking plentiful inflated cells; spores never dominantly elongate; not yet reported from Mesoamerica..
              17. Spores (of A. elliptosperma): (8.0-) 8.7 - 11.2 (-11.5) (5.8-) 5.9 - 7.5 (-7.8) m, with Q = 1.40 - 1.50; the various taxa listed in this "group" were described from the states of Florida (Murrill's taxa) and  North Carolina (Coker's taxa), USA; known from mixed forest or in association with Oak (Quercus) from as far north as the state of New York, USA, and well south into Central America.

Amanita elliptosperma G. F. Atk.
=? Amanita gwyniana Coker
=? Amanita hygroscopica Coker
=? Amanita parviformis (Murrill) Murrill
=? Amanita pseudoverna (Murrill) Murrill
=? Amanita verniformis (Murrill) Murrill.

Notes: All the taxa were described originally as white.  Amanita hygroscopica was described as having pinkish lamellae; however, this is not a constant character in other Amanita taxa, and RET has seen numerous shades ranging from white to cream to  pink in gills of  species of this group. Amanita gwyniana was described as having a "chloride of lime" odor; however, the same (or similar) odor can be detected in fresh material assignable to A. elliptosperma and A. sp. S4.  This group seems to be more common, as a whole, than A. magnivelaris.
RET has never found any specimen assignable to this group that turned yellow with KOH.  The response to KOH is omitted from the original descriptions in all cases.  The Murrill taxa were collected in the sandy coastal plain of Florida and are sometimes based on small specimens, possibly depauperate examples of the taxa considered to be larger "taxa."  Unfortunately, the current condition of types is not conducive to definitive molecular or morphological judgments on taxonomic synonymy using present methods. Spore data from my type studies follow:

A. elliptosperma - (8.0-) 8.8 - 11.2 (-11.5) (5.8-) 6.0 - 7.2 (-7.8) m, with Q = 1.48  [type includes single specimen]

A. gwyniana - (8.4-) 8.9 - 11.8 (-12.4) 6.0 - 8.0 (-8.7) m, with Q = 1.46 - 1.54 [type includes two specimens]

A. hygroscopica - study not yet complete

A. parviformis - (8.2-) 8.8 - 10.0 (-11.2) (5.2-) 5.5 - 7.0 (-7.2) m, with Q = 1.49 [type includes single specimen]

A. pseudoverna - 9.0 - 10.8 (-12.0) 6.2 - 8.0 (-8.2) m, with Q = 1.39 - 1.41 [one of three specimens in type was excluded per Bas' notes on type]

A. verniformis - (9.0-) 9.2 - 11.2 (-11.8) 6.5 - 8.2 m, with Q = 1.37 [type includes single specimen]

 

                17. Spores: (7.3-) 8.4 - 11.2 (-13.5) (4.9-) 5.5 - 6.8 (-8.5) m, with Q = 1.50 - 1.60 (-1.69).  Possibly, not distinct from one or more of the taxa listed in the previous key entry.  Known not to turn yellow with KOH

Amanita sp. S4 [Tulloss].

 

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Last change 19 March 2007.
Original conversion to HTML format by Dr. Michael Kuo.
Copyright 2003, 2005, 2006, 2007 by Rodham E. Tulloss.