The fruiting bodies of A. sphaerobulbosa are usually small. The cap is 20-40 mm wide, convex to applanate, white to creamy, and with an appendiculate margin. It is covered with conical to subconical, small, white warts that are about 1 mm high; its flesh is white.
The gills of this species are free to subfree, crowded, and white to cream-colored; and the short gills are attenuate and of diverse lengths.
The stipe is 50 - 80 × 5 - 8 mm, subcylindric to attenuate upwards; its
surface is white to dirty white. The stipe's basal bulb is 15 - 25 mm
wide, subabrupt to abrupt, marginate, with the upper margin covered
with whitish, small volval remnants. The annulus is membranous and
superior, persistent or fugacious.
Spores measure (7.0-) 8.0-10.5 (-11.5) × (6.5-) 7.0-9.5 (-10.0) µm
and are globose, subglobose to broadly ellipsoid, and amyloid. Clamps are present on the bases of basidia.
Amanita sphaerobulbosa was originally described from Japan. It may also occur in China, but
no authentic material has been examined. It occurs in mixed forests with broad-leaved trees and conifers.
Amanita sphaerobulbosa is very similar to A. abrupta Peck, and the
names have often been regarded as synonyms. Undoubtedly, they are very closely related to each other. However, the
spores of A. abrupta are much narrower. Furthermore, in A.
sphaerobulbosa, many hyphae and inflated cells, especially in the upper part of volval
remnants on pileus, are vascular (oleiferous), i.e., have refractive contents; this is not the case in
A. abrupta. The partial veil of A. abrupta is very persistent (rarely, if ever, fugacioius).—Z. L. Yang
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TNS [per Doi. 1991. Bull. Natl. Sci. Mus., Tokyo, Ser. B 17(2): 50]
Z. L. Yang and Y. Doi. 1999. Bull. Natl. Sci. Mus. Tokyo B 25(3): 119-120, figs. 17-19.
Imazeki and Hongo. 1987. Color. Illus. Mushr. Japan 1: 132, pl. 33 (fig. 229). [As "Amanita abrupta."]
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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this text is appropriate.
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 not directly from the protolog of the present taxon and not cited as the work of Dr. Z. L. Yang or another researcher is based upon original research by R. E. Tulloss.
NOTE: Spore measurements from papers by Z. L. Yang use his "Times New Roman" face for "Q"
and "Q'"—respectively, "Q" and "Q."
From Yang and Doi (1999): [105/5/5] (7.0-) 8.0 - 10.5 (-11.5) × (6.5-) 7.0 - 9.5 (-10.0) μm, (Q = (1.0-) 1.02 - 1.18 (-1.25); Q = 1.10 ± 0.05), hyaline, colorless, smooth, thin-walled, amyloid, globose to subglobose to (occasionally) broadly ellipsoid; apiculus small.
composite spore data from material revised by RET: [25/1/1] (7.8-) 8.1 - 11.0 (-11.9) × 7.4 - 9.8 (-10.3) μm,
(L = 9.2 μm; W = 8.4 μm; Q = 1.04 - 1.20 (-1.26); Q = 1.10), subhyaline, colorless, smooth, thin-walled, amyloid, globose to subglobose to broadly ellipsoid, often adaxially flattened, with "giant" spores sometimes present; apiculus sublateral, cylindric; contents multiguttulate; color in deposit not recorded.
Japan: In Fagus forest or in Quercus forest.
from protolog: JAPAN: HONSHU—Shiga-ken - Mt. Watamuki, 17.ix.1967 T. Hongo 3504 (holotype, in herb. Hongo => TNS F-244377).
from Yang and Doi (1999): JAPAN: HONSHU—Shiga-ken - Mt. Watamuki, 17.ix.1967 T. Hongo 3504 (holotype, in herb. Hongo => TNS F-244377). Tokyo Metropolis (Pref.) - Oume-shi, Kurosawa 3-chôme, Nagayama-Kyûryô Hills, along hiking course, 5.x.1997 Y. Doi s.n. (TNS F-237770); Oume-shi, Kurosawa 3-chôme, right side of Kurosawa-gawa R., 25.ix.1997 Y. Doi S.n. (TNS F-237949), 2.viii.1997 Y. Doi & K. Miyazaki s.n. (TNS F-182502); Oume-shi, Kurosawa 3-chôme, Nagayama-Kyûryô Hills, left-side of Kurosawa-gawa R., along hiking course, 5.x.1997 Y. Doi & K. Miyazaki s.n. (TNS F-237569).
UNKN. ISL.—Unkn. Prefecture - unkn. loc., s.d. unkn. coll. s.n. [Borovička B 381] (PRM, RET 455-10).
For a number of years this species was confused with the North American species A. abrupta; however, the two taxa are now seen as clearly distinct. They are both assignable to Bas' stirps Microlepis. It would be very interesting to know if a syringaldazine spot text of the east Asian species would produce the dramatic purple (positive) response for the presence of laccase that the North American taxon produces. Sporographs of the two species are compared in the following figure:
The Japanese name for the present species is "tama-shiro-onitake" (Doi 1991).
—R. E. Tulloss
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