Amanita hamadae - Amanitaceae.org - Taxonomy and Morphology of Amanita and Limacella
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name Amanita hamadae
name status nomen acceptum
author Nagas. & Hongo
english name "Hamada's Ringless Amanita"
intro

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

cap

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.

gills

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.

stem 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 in the original collection. 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/taste

Odor and taste are indistinct.

spores

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.

discussion

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 can be questioned 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 of stirps Hemibapha having spores approximately equally distributed between broadly ellipsoid and ellipsoid, Amanita hamadae is the only species known without bright colors.

The original description of A. hamadae includes brief mention of a gelatinized suprapellis (upper layer of cap skin) including hyphae with yellow content. We are not sure how to interpret this statement; but, if this describes a gelatinized matrix through which ungelatinized colored hyphae run, then we should point to a group of taxa with a similar cap skin that has a tropical distribution and includes 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 of A. hamadae are vascular hyphae [hyphae with refractive content that rarely have cross-walls (septa)] or are not part of the Amanita but of an attacking mold.—R. E. Tulloss and L. Possiel

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