Amanita mappa - Amanitaceae.org - Taxonomy and Morphology of Amanita and Limacella
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name Amanita mappa
name status nomen acceptum
author (Batsch) Fr.
english name "Citrin Bulbous Amanita"
synonyms
≡Amanita citrina (Schaeff.) Pers.
=Amanita bulbosa (Schaeff.) Lam.
images


  • 1. Amanita mappa, England.


  • 2. Amanita mappa (white variant), Scotland, U.K.


  • 3. Amanita mappa (white variant), Italy.


  • 4. Amanita mappa (white variant), Italy.



  • 5. Amanita mappa (white varianta), Italy.

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    The following is based on the description by Neville and Poumarat (2004) and data from RET (based on field notes concerning English and Scottish material).
    cap The cap of Amanita mappa is 40 - 100 mm wide, whitish yellow to citron yellow, with pigment most saturated in the center.  A white variant is sometimes encountered.  The cap is sometimes touched with rusty brown here and there; it is hemispheric then convex, plano-convex, and finally planar.  It usually lacks an umbo.  It is smooth, shiny to subshiny; and, although tacky or slightly viscid at first, it dries quickly.  Its margin is nonstriate and nonappendiculate.  Volval remnants are absent or present as citron or pallid submembranous patches or clusters of breakable warts or fibrillose, concentrically arranged scales.  These become pale brown to brownish to brownish white and are easily removable.  The cap's flesh is white, tinted citron just below the cap skin when the cap surface is not white.
    gills The gills are free to narrowly adnate, rather crowded, very pale orangish white to cream to white to citron tinted white, 5 - 10 mm broad, with a decurrent line on the stem and a finely fibrillose edge.  The short gills are truncate to rounded truncate to subattenuate and plentiful.
    stem The stem is 50 - 150 × 6 - 23 mm, satiny, cylindric or slightly narrowing upward, stuffed becoming hollow, white (sometimes tinted citron above the ring at, and sometimes appears to be sheathed with pale citron yellow material.  The stipe's bulb is 20 - 40 × 21 - 40 mm and marginate, subhemispherical to subglobose.  The stem's ring is membranous, skirt-like, rather thin with a thickened edge, and located on the upper part of the stem; it is pale citron yellow when the cap is yellowish (otherwise white) and browns in age. It is finely striate on its upper side in young specimens and finely flocculose on the edge and on the underside especially near the edge.  The ring eventually collapses on the stem.  The volva is present as an (often) rather short limb or limbs irregularly distributed on the stipe's bulb or as a white to browning ridge on the outer edge of the flattened upper surface of the bulb.  The stem's flesh is white and unchanging.
    odor/taste The odor is radish-like or like freshly dug potatoes.
    spores RET spore measurements from yellow-capped material are (6.9-) 7.5 - 10.0 (-16.0) × (6.0-) 7.0 - 8.8 (-10.4) µm and are globose to subglobose, rarely broadly ellipsoid or ellipsoid, and amyloid.  Clamps are absent from bases of basidia.

    Spores measurements from yellow-capped specimens, based on a larger sample of Neville and Poumarat (2004) are 7 - 9 (-9.5) × 6 - 8.5 (-9) µm and are globose to subglobose to broadly ellipsoid.

    RET spore measurements from white-capped material are (7.0-) 7.6 - 8.5 (-9.0) × (6.5-) 7.2 - 7.9 (-8.0) µm and are globose to subglobose, rarely broadly ellipsoid or ellipsoid, and amyloid.  Clamps are absent from bases of basidia.

    Spore measurements from white-capped specimens based on a larger sample of Neville and Poumarat (2004) are (7.5-) 8 - 9.5 (-10) × (6.5-) 7 - 8.5 (-9) µm and are globose to subglobose to broadly ellipsoid, rarely ellipsoid.
    discussion This species (both color variants) is known from Europe and western Asia.  Neville and Poumarat state that this mushroom may occur up to an altitude of 1200 m from spring to late autumn in Europe.  These authors include an extended list of potential host trees including pines (e.g., Pinus pinaster and P. strobus) spruces (e.g., Picea abies) as well as broad-leafed species such as birch (Betula), Chestnut (Castanea sativa), European Beech (Fagus sylvatica), alien eucalypts (e.g., Eucalyptus glabulus), and oaks (e.g., Quercus suber).  This species will be found in field guides or species list under a variety of names such as A. citrina, A. citrina var. alba, A. bulbosa, or A. bulbosa var. citrina.  The color variants of A. mappa do not correspond to genetically separable groups.  The correct name for the species is the one used to designate this page.

    The mushrooms known as "A. citrina" in North America are at least three distinct species, one of which is A. lavendula.  Whe when temperatures approach freezing, all the known North American species may exhibit lavender or deeper purple staining or bruising).  This color change is not reported for the present species.

    Asian material ascribed to this species is more likely A. sinocitrina Zhu L. Yang, Z. H. Chen & Z. G. Zhang or A. citrina var. grisea (Hongo) Hongo.—R. E. Tulloss
    brief editors RET

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