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[ Section Validae page. ] [ Amanita Studies home. ] [ Keys & Checklist/Picturebooks ] Amanita flavorubens (Berk. & Mont.) Sacc."Yellow American Blusher" =Amanita flavorubescens G. F. Atk. Technical description. (t.b.d.) BRIEF DESCRIPTION: The following is based on the description by Montagne (1856) and personal data from RET. The cap of Amanita flavorubens is 35 - 105 mm wide, yellow to brassy yellow to lemon yellow, sometimes dark orange brown, sometimes with pigment entirely washed out by rain becoming pallid, sometimes very deep wine red in its entirety due to bruising during development (Coker 1917), subovoid to hemispheric to plano-convex to convex, depressed in the center, slightly tacky to dull to subviscid to subvelvety, with an incurved or downcurved, rimose, and nonstriate margin (may become slightly striate with age). The volva is present as yellow to orange to bright orange-yellow flocculent to confluent warts, friable, sparsely and irregularly distributed, easily removable, pulverulent, splotchy brown around the center, yellow at the edge. The flesh is 3 - 7 mm thick over the stem, thinning evenly to the margin, white or yellowish, bright yellow just under the cap skin. The gills are free to very narrowly adnate, subcrowded to crowded, creamy ivory to cream to off-white, 3 - 8 mm broad, with a white pulverulent edge and a small decurrent tooth. The short gills are truncate to subtruncate to subattenuate to attenuate to attenuate in steps, unevenly distributed, of diverse lengths, and plentiful. The stem is 52 - 150 × 7 - 14 mm, usually narrowing upward, infrequently narrowing downward, flaring at the top, yellow to white or very pale yellowish white and pruinose to finely powdery above the ring, white to yellow or occasionally with scattered yellowish surface fibrils and fibrillose below the ring, sometimes silky longitudinally striate. The bulb is 15 - 25 × 15 - 21 mm, more or less turnip-shaped, with light red-pinkish stains; interior of the bulb is often the place where wine-red staining first appears intensely. The ring is membranous, superior, skirt-like, flaring then collapsing, pale yellowish white to cream to white, slightly more yellow underneath, with a thickened edge. The volva is absent or present as rings of yellow-brown warts on the bulb or brilliant yellow loose patches appressed to the stem and are large, friable, detersile, sometimes lost during collecting. The flesh is white or slightly pink, hollow or partially hollowed in the middle to stuffed. The odor is of clean laundry. The spores measure (7.4-) 7.8 - 11.0 (-12.6) x (4.9-) 5.4 - 7.0 (-8.4) µm and are ellipsoid to elongate (infrequently broadly ellipsoid) and amyloid. Clamps are not present at bases of basidia. This species was originally described from the state of Ohio, USA and is known from forests associated with beech (Fagus grandifolia), oak (Quercus), pine (Pinus), birch (Betula), and Canadian hemlock (Tsuga canadensis) from southeastern Canada to Alabama in eastern North America, central Mexico, and southeastern Arizona. Rain will quickly wash pigment away from the yellow-orange pileus. Bruising is sometimes reported only from the stem base for this species, but it commonly bruises throughout the fruiting body. Occasionally, especially in areas with dense root mats, specimens will be found in which the entire pileus is wine-colored from bruising during expansion through the root mat. RET has found one specimen with the cap intensely bruised (see photo: top row center) before expansion as described by Coker (see above). The cap was dark red brown in the center and elsewhere ranged from brown to pale yellow brown at the cap margin. The cap warts were in concentric rings and somewhat concolorous with the surrounding cap skin, but always with a distinct yellow tint. In the original description, the authors of this species mention its similarity to Amanita rubescens Pers. : Fr. of Europe; in the watercolors of George Morris (Peabody Museum, Salem, Mass., USA) the present species is labeled yellow form of A. rubescens. It seems clear that the rubescent taxa of eastern North America (the present species, A. rubescens var. alba Coker, and A. rubescens in the sense of eastern North American authors) do form a closely related group. In addition to the bruising reactions, all three of them at least occasionally have a yellow volva. The present species can be differentiated from its two sister taxa because of the color of the cap, frequently slower staining reaction, spores that are on average longer, and spores that on average are proportionately narrower. For distinguishing between rubescent taxa in section Validae, refer to the Key of rubescent taxa in Amanita section Validae. Amanita flavorubens is one of the few
taxa in North America in which there is a western population disjunct
from an eastern primary area of distribution. Photos: R. E. Tulloss (top left, Connecticut, U.S.A.; top center, top right, bottom right, New Jersey; bottom left, Arizona, U.S.A.;) [ Section Validae page. ] [ Amanita Studies home. ] [ Keys & Checklist/Picturebooks ] Last changed 6 July 2008. |
