Amanita xanthocephala - Amanitaceae.org - Taxonomy and Morphology of Amanita and Limacella
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name Amanita xanthocephala
name status nomen acceptum
author (Berk.) D. A. Reid & R. N. Hilton
english name "Vermilion Amanita"
images
  • Amanita xanthocephala, ca. Bundanoon, New South Wales, Australia.Amanita xanthocephala, ca. Bundanoon, New South Wales, Australia.

    1. Amanita xanthocephala, ca. Bundanoon, New South Wales, Australia.

  • Amanita xanthocephala, ca. Bundanoon, New South Wales, Australia.Amanita xanthocephala, ca. Bundanoon, New South Wales, Australia.

    2. Amanita xanthocephala, ca. Bundanoon, New South Wales, Australia.

  • Amanita xanthocephala (Cooke's plate of Agaricus pulchellus), Domain, Victoria, Australia. Note artist's addition of non-existent robust, saccate volva to stipe base.Amanita xanthocephala (Cooke's plate of Agaricus pulchellus), Domain, Victoria, Australia. Note artist's addition of non-existent robust, saccate volva to stipe base.

    3. Amanita xanthocephala (Cooke's plate of Agaricus pulchellus), Domain, Victoria, Australia. Note artist's addition of non-existent robust, saccate volva to stipe base.

    • intro The following combines the original description of the species with descriptions from Reid (1980), Grgurinovic (1997), and Wood (1997) and the information that can be gathered from recent photographs and their voucher specimens.  Collections with photographs and notes on fresh material that improve this description are welcomed by the editors of these pages.
    cap The convex cap of A. xanthocephala is 25 - 50 (or more) mm wide, orange-yellow to red-orange with its center often most intensely reddish.  The margin is strongly striate and nonappendiculate.  The volval warts on the pileus are described as red, yellow, and white in the available literature—without comment on the range of colors (apparently they begin as orange or red in young material and fade to off-white or white from the top down).  The volval remnants are fibrillose at their base and rather easily removable.
    gills The gills are crowded and white; the short gills are truncate, infrequent, and widely scattered.
    stem The ringless stem is about 30 - 62 × up to 7 mm (bulb included in length), slender, narrowing upward, white (often with pale yellow tints), and stains tannish from handling.  The stem's bulb is ellipsoid to broadly spindle-shaped.  The upper part of the bulb bears an irregular, sometimes a bit lumpy, ring of yellow to orange-yellow volval material (probably originally as red as the material on the young cap).
    spores Spore data from the literature varies considerably.  We are able to identify two apparent groups of measurements based on comparison by sporographs (see the technical tab for this page).  The group with more globose spores seem associated with eastern collections (from New South Wales, Victoria, and the Australian Capital Territory).  A group with more ellipsoid spores seems associated with collections from Western Australia.  HL measured spores from four recent collections of this species found in the Australian Capital Territory and SE New South Wales and got the following results: (6.4-) 7.2 - 8.8 (-9.6) × 6.4 - 8.0 (-8.4) µm; These measurements well-represent the eastern group with average spores subglobose.  The Western groups spores are known from samples of unknown size reported by Reid (1980); for example, Reid reported spores as follows from a single collection: 6.5 - 9.2 × 5.5 - 6.8 μm.  A single collection from Mt. Lofty, South Australia, was reported to have ellipsoid spores by Gilbert (1940); a range derived from his spore drawings follows: 10.0 - 10.9 × 7.0 - 8.6 μm.  Could this represent a third spore-form within a very broad concept of A. xanthocephala?

    The spores are inamyloid.  Clamps are lacking at bases of basidia.
    discussion Amanita xanthocephala occurs with Eucalyptus.

    This species somewhat resembles another species that lacks basidial clamps, has globose to subglobose spores, pileus in the red-orange range and reddish volva that becomes yellowish or pallid with age or exposure—A. rubrovolvata S. Imai of SE and E Asia.  However, among other differences, the latter species has a persistent annulus and (usually) an intensely yellow stipe.

    Amanita xanthocephala was originally described from the state of Western Australia (as Agaricus xanthocephalus) and from Victoria (as Agaricus pulchellus Cooke & Massee).  Under the present concept (see spore discussion above) this mushroom is reported from eucalypt forest regions extending from Western Australia eastward through the southern coastal states of the continent and, thence, north to Queensland.—R. E. Tulloss and H. Lepp
    brief editors RET

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