Amanita umbilicata - Amanitaceae.org - Taxonomy and Morphology of Amanita and Limacella
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name Amanita umbilicata
name status nomen provisorum
author Tulloss, Kudzma, K. W. Hughes, I. Safonov
english name "Dimpled Amanita"
intro Information below is derived from original research by RET and CRC.
cap The cap of Amanita umbilicata is 30 - 57 mm wide, yellow-brown over disc, grayish yellow or light orangish yellow (4A3) toward the cap's edge, convex to flattened-concave, with a shallow distinct indentation in the center in all stages of expansion, dry.  The cap's flesh is yellowish white, 2 mm thick above stipe, unchanging, in older material thinning to a membrane 5 - 6 mm from the cap's edge.  Usually the cap's edge lacks radial grooves; however, sometimes such grooves are present in age, but are short (with length less than 10% of cap's radius) in age.  The volval remnants on the cap are submembranous flat irregular patches, yellow to pale yellowish gray to yellowish gray to grayish yellow to light grayish tan, sometimes becoming closer to the cap's coloring where drying has occurred.
gills The gills of A. umbilicata are adnate with a decurrent line descending the top of the stem.  They are pale yellow-cream in mass and off-white in side view, without staining or bruising.  The gills are up to 4 mm broad at mid-length.  The plentiful short gills are unevenly distributed, of diverse lengths, and are not squarely cut-off on the end toward the stem.
stem The pale yellow-white to pale yellow stem of this species measures 42 - 72 × 2.5 - 8 mm and becomes reddish brown to golden brown to brownish gray from handling.  The stem's bulb is 12 - 6 × 7 - 11 mm.  The stem is hollow with a central cylinder 4.0 - 4.5 mm wide, and its is probably whitish; sometimes the central cylinder develops a reddish brown interior surface.  The stem's membranous to submembranous ring varies in position between the top and the middle of the stem and become detached and fall on to the stem's bulb.  The ring is yellowish white to pale yellow on the upper surface and sometimes becomes golden yellow toward free edge; the lower surface is pale yellowish cream.  No volval remnants have been found on the stem in the specimens that have been reviewed.
odor/taste The odor of this species is indistinct, but pleasant, with older specimens having slight odor of sodium hypochloride.  Taste is lacking or faintly like a toy balloon.
spores The spores of this species measure (7.0-) 7.3 - 9.4 (-10.2) × (4.8-) 4.9 - 6.1 (-6.4) μm and are ellipsoid to elongate and amyloid.  Clamps are absent from bases of basidia.
discussion This species is genetically separable from all other rubescent taxa researched by the authors of this description.  Amanita umbilicata is known from a single, New Jersey collection found in deep, sandy soil of Pinus rigida-Quercus barrens.—R. E. Tulloss, C. Rodríguez Caycedo and K. W. Hughes
brief editors RET

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