Amanita brunneibulbosa - Amanitaceae.org - Taxonomy and Morphology of Amanita and Limacella
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name Amanita brunneibulbosa
name status nomen acceptum
author O. K. Mill.
english name "Miller's Slender Amanita"
images
intro The following is based on the original description of Miller (1992).
cap The cap of Amanita brunneibulbosa is 38 - 44 (-50) mm wide, conic to convex then planar in age, viscid, glabrous, brown, with a nonstriate margin, sometimes appendiculate in young material.  The volva is present on the cap as light gray, powder areas, which are present at the margin in young material or as loose, white, easily removed patches over the center and (at times) irregularly elsewhere on the cap.  The flesh is white, firm, and unchanging.
gills The gills are subdistant, narrowly adnate, broad, white, sometimes becoming buff in age.  Short gills are said to be present in a single tier.
stem The stem is 75 - 110 × 4 - 7 mm, cylindric white covered with minute fibrils, tinted cream to buff.  The basal bulb is subglobose, marginate to submarginate, 13 - 23 × 13 - 20 mm.  The volva is white and submembranous and is visible as rings of tissue on the base, tinted cream to buff.  The ring is dull white to grayish white, very fragile, sometimes present as a ragged skirt, sometimes absent.  The flesh is white, firm, and unchanging.
odor/taste The odor of the present species is said to be indistinct, and its taste has not been recorded.
spores The spores measure 8 - 10 × 5 - 6.5 µm and are ellipsoid to elongate and amyloid. Clamps are absent at bases of basidia.
discussion The present species was originally described from the state of Western Australia where it occurs gregariously in litter under Eucalyptus.

Miller proposed placement of A. brunneibulbosa in section Phalloideae.  On the other hand, Miller states the most similar species is A. gossypino-annulata D. A. Reid, which is rather securely placed in section Lepidella.

The original description is not clear about the nature of the volva in relation to the stem's bulb.  In the accompanying photograph, the volva appears to be present on the lower stem as loose, appressed patches, not as a membranous limb attached to the bulb (as is typical of sect. Phalloideae).  The pileus pigmentation suggests "radially oriented innate hairs" in the photograph.  A ring is present although possibly damaged on the stem of every specimen in the photograph, thus suggesting any fragility has more to do with its thinness than with a microscopic structure that might argue for placement in section Lepidella.

A submembranous, white volva that becomes tinted buff or gray is known in a number of species of sect. Validae.  The absence of clamps and the small, but elongate, spores are also consistent with placement in sect. Validae.  Therefore, at least for the moment, I propose the placement of this species in the latter section.—R. E. Tulloss
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