Amanita xanthocephala : Vermilion Amanita

Technical description (t.b.d.)

BRIEF DESCRIPTION

This description 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.

The convex cap of Amanita xanthocephala is 25 – 50 (or more) mm wide, orange-yellow to red-orange with its center

Amanita xanthocephala 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.

The gills are crowded and white; the short gills are truncate, infrequent, and widely scattered.

Amanita xanthocephala

The stipe 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 stipe’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).

The spores are reported to be (6.6-) 7.2 – 10.8 × 5.7 – 8.8 µm and are globose to subglobose to broadly ellipsoid and inamyloid (Reid, 1980; Wood, 1997). Heino Lepp 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 had a greater tendency to be globose than is indicated in the cited literature. Clamps are lacking at bases of basidia.

Amanita xanthocephala occurs with Eucalyptus.

This species somewhat resembles another species that lacks basidial clamps, has globose to subglobose to 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 West Australia (as Agaricus xanthocephalus) and from Victoria (as Agaricus pulchellus Cooke & Massee), it is reported from eucalypt forest regions extending from West Australia east and north to Queensland. The Australian Fungimap project page is http://fungimap.rbg.vic.gov.au/fsp/sp002.html. — R. E. Tulloss and H. Lepp

Photo: Heino Lepp (Australian Capital Territory, Australia)