The content herein is derived from the original description (Zhang et al., 2010).
The fruiting body of Amanita rimosa is small to medium-sized. The cap is 48± mm wide, convex to flattened, undecorated, pale buff in the center, dirty white toward the margin, and raidally splitting around the margin (minutely or with flesh splitting for about half of the cap's radius). The cap's margin is non-striate and non-appendiculate, and its flesh is white.
The gills are free, white to whitish, subcrowded, and up to 5 mm broad. The short gills are attenuate, plentiful, and in 2-3 ranks.
The stem is 70 mm long, nearly cylindric, slightly tapering upward, with an apex that is slightly expanded. The stem is 7 mm wide at the top and 10 mm wide near the base. It is white to whitish, solid, and is decorated with with finely fibrillose squamules. Its flesh is white. The basal bulb of the stem is subglobose and 16 mm wide. The volva is limbate, membranous, rather firm, with free limb up to 8 mm high, and both its surfaces are white. The stem's ring is is placed near the top of the stem anid is thin, skirt-like, and membranous.
The odor is indistinct. This species is very probably deadly POISONOUS.
The spores measure 7.0 - 8.5 (-10.0) × 6.5 - 8.0 (-9.0) µm and are globose to subglobose and amyloid. The basidia are clampless.
Amanita rimosa grows in a broad-leaved forest dominated by Fagaceae [trees of the Beech-Oak family]. This mushroom is only known from the type locality (China, Hunan Province, Yizhang County, Mangshan) at present.
A remarkable feature of Amanita rimosa is its splitting cap surface, which is a result of the mushroom's having a slightly gelatinized upper layer of the cap's skin that includes abundant inflated cells. As a result, the structure of this skin is much weaker than is the case in nearly all known amanitas.
The fruiting body becomes yellow when wetted with 5% KOH (potassium hydroxide) solution.
Based on the close phylogenetic relationship with other lethal Amanita species, the present species must be deadly poisonous. More information and a key to the taxa of sect. Phalloideae in East Asia can be fund from Zhang et al. (2010).—P. Zhang and Z.-L. Yang
P. Zhang & Zhu L. Yang. in P. Zhang et al. 2010. Fungal Diversity 42: 124, figs. 2, 8-9.
Zhang et al. (2010), Key Lab. Biodivers. Biogeogr., Kunming Inst. Bot., Yunnan, China
The following text may make multiple use of each data field.
The field may contain magenta text presenting data from a type study
and/or revision of other original material cited in the protolog of the present taxon.
Macroscopic descriptions in magenta are a combination of data from the protolog and
additional observations made on the exiccata during revision of the cited original
The same field may also contain black text, which is data from a revision of the present
taxon (including non-type material and/or material not cited in the protolog).
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Olive text indicates a specimen that has not been
thoroughly examined (for example, for microscopic details) and marks other places in the text
where data is missing or uncertain.
The following material is derived from the protolog of the present species.
NOTE: Spore measurements from papers following the notation of Z. L. Yang use his "Times New Roman" face for "Q"
and "Q'"—respectively, "Q" and "Q."
Having an upper layer comprising inflated, ellipsoid to clavate to fusiform, almost colorless, hyaline terminal cells (50 - 280 × 15 - 40 µm).
Each spore data set is intended to comprise a set of measurements from a single specimen made by a single observer;
and explanations prepared for this site talk about specimen-observer pairs associated with each data set.
Combining more data into a single data set is non-optimal because it obscures observer differences
(which may be valuable for instructional purposes, for example) and may obscure instances in which
a single collection inadvertently contains a mixture of taxa.