Technical description (t.b.d.)

BRIEF DESCRIPTION: The following description is based on the original description by Nagasawa and Hongo (1984).

The cap of A. hamadae is 45 - 70 mm wide, yellowish-brown to brown or olive-brown over the center, grayish yellow towards the margin in maturity, light yellow to yellow around the margin when young, campanulate at first, then becoming convex to planar with a significant umbo, subviscid when moist, with a strongly sulcate-striate margin. The flesh is thin, white, yellow under the cap skin.

The gills are free, subcrowded, 4 - 7 mm broad, whitish, becoming somewhat pinkish with age, with a yellow subflocculose edge. The short gills are truncate.

The stem is 100 - 130 × 4 - 10 mm, slightly tapering upward, hollow, sulfur yellow to light yellow or grayish yellow, except for the lower third which is tinged with salmon color, and fibrillose-scaly except for its bottom-most portion [Note: illustration shows decoration is in a pattern often called zebroid, flame, or snakeskin.]. A bulb and ring are absent. The saccate volva is 20 - 40 × 15 - 20 mm, membranous, attached only at the very base of the stem, with a light yellow tint in the upper part of the limb, and with a fringed internal limb. The flesh is thin, white, yellow under the skin, pinkish at the base of the stem.

Odor and taste are indistinct.

The spores measure 10 - 12 (-13) × (7-) 7.5 - 9 (-11) µm and are broadly ellipsoid to ellipsoid and inamyloid. Clamps are absent at bases of basidia.

This species occurs alone or in groups in association with Abies-Castanopsis forests, especially under A. firma and was originally described from western Japan.

While the colors, spore shape, and habit of the present species suggest a relationship to the Slender Caesars (stirps Hemibapha), this relationship cannot be close because this species lacks a ring and lacks clamps throughout the fruiting body including the basidia. In addition, assuming that the illustration of the basidia and subhymenium is correct, the subhymenium is not composed of layers of roughly globose cells as it is in stirps Hemibapha.  

Among the known taxa with spores approximately equally distributed between broadly ellipsoid and ellipsoid, Amanita hamadae is the only species known with bright colors except for A. hovae Bouriquet, a little known species from Madagascar. The original description includes a brief mention of a gelatinized suprapellis (upper layer of cap skin) including hyphae with yellow content. We are not sure how to interpret this but if this described a gelatinized matrix through with ungelatinized colored hyphae run, then the closely related taxa would have tropical distribution and include A. sampajensis A. V. Sathe & S. M. Kulk., A. flammeola Pegler & Pierce, and A. dunicola Guzmán. It is also possible that the hyphae observed in the suprapellis in A. hamadae are not part of the Amanita but of an attacking mold.  -- R. E. Tulloss and L. Possiel

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Last change 7 July 2006
This page is maintained by R. E. Tulloss.
Copyright 2006 by Rodham E. Tulloss.