Amanita subglobosa : Ringed-Bulb Amanita

Amanita subglobosa
Amanita subglobosa
Amanita subglobosa

 

Technical description (t.b.d.)

BRIEF DESCRIPTION

Fruiting bodies of Amanita subglobosa are medium-sized to large, or occasionally small. The cap is 40 – 100 (-150) mm wide, convex to applanate, sometimes concave, brownish to brown to cinnamon-buff, darker in the center, densely covered with white, dirty white to yellowish, conical to verrucose volval remnants 1 – 2 mm high and 1 – 2.5 mm wide; the cap’s margin is striate (10% to 40% of radius) and non-appendiculate; the cap’s context is white.

The gills are free to subfree and white to cream; the short gills are truncate.

The stipe is 50 – 150 (-240) x 5 – 20 (-30) mm, subcylindric, cream to white, and fibrillose; the stipe’s basal bulb is 15 – 35 mm wide and subglobose, with its upper part covered with white, or sometimes yellowish to brownish, verrucose, granular to farinose volval remnants. There is often a collar encircling the base of the stipe and atop the bulb. The annulus is membranous, white, often on the upper part of stipe, although sometimes almost median, and persistent.

The spores measure (7.5-) 8.5 – 12.0 (-15.0) x (6.0-) 7.0 – 9.5 (-12.5) µm and are broadly ellipsoid to ellipsoid, or rarely subglobose or elongate and inamyloid. Clamps are common on the bases of basidia.

Originally described from southwestern China and widely distributed in that country, this species probably occurs in Japan also.

Although this species’ general appearance suggests Amanita pantherina (DC.:Fr.) Krombh., that species lacks clamps at the bases of basidia. Plentiful clamps is a character A. subglobosa shares with the species phenetically similar to A. muscaria (L.:Fr.) Pers. For a very similar species described recently from Japan, see A. ibotengutake T. Oda, C. Tanaka & Tsuda. — Zhu L. Yang.

Photos: M.-S. Yuan (left, holotype, Sichuan Prov., China), Zhu L. Yang (center & right, Yunnan Prov., China)