=Amanita inaurata Secr. f. americana E.-J. Gilbert nom. nud. sensu Singer. 1963. Mycopathol. Mycol. Appl. 20: 241. [Gilbert (1940-1941) listed no type and provided no Latin diagnosis.]

Brief description

TECHNICAL DESCRIPTION (incomplete segments in pale olive type).

Etymology: sororcula, little sister, because A. ceciliae, with which this species has been confused, was named for Berkeley's daughter, Cecilia -- metaphorically the "older sister" species.

PILEUS: 35 - 85 mm wide, gray to smoky gray (61 g Br.) to brownish gray (7E3) to grayish brown (6D-F4) or to "soapstone" (MP) to dark brown (6F8 or 7F5) to chocolate to fuscous to deep fuscous to dark grayish brown (7F3); usually darkest over disc (e.g., 6F4 to 8F3), sometimes uniformly pigmented, at first rounded subconic to convex, then broadly convex to campanulate, subumbonate to umbonate, dry, subpolished to shiny; context white, but blackish under pileipellis, unchanging when cut, 4 - 5 mm thick; margin sulcate or pectinate (0.25R - 0.5R), sometimes decurved, flaring upward at maturity, nonappendiculate; universal veil as scattered appressed patches or truncate conic or conic warts, white or whitish at first, becoming orangish gray to brownish gray (6B-C2) to grayish to tannish gray (5C3) to dark grayish brown (6F4), sometimes paler on sides than on upper surface, sometimesly nearly black in exsiccata.

LAMELLAE: free, close to crowded, white to whitish buff, becoming gray from margin inward, with white to grayish to dark gray to brownish gray (6C2) to dark brownish gray (7E3) to dark grayish brown (8F3) to "soapstone" (MP) fimbriate edges, drying 4A3 or slightly grayer than 4A4 to 5B4 or dark gray to yellowish gray (5Y 7/4) and always retaining brownish edge, rather thin to rather thick, 3 - 8 mm broad; lamellulae truncate to subtruncate, of diverse lengths, unevenly distributed.

STIPE: 70 - 150 × 7 - 15⁺ mm, subcylindric or tapering upwards, with ground color white (at least above) to sometimes grayish toward base, with surface decorated with fine appressed grayish to brownish gray to grayish brown (6-7E3) fibrils often in belts; context white, unchanging when cut or bruised, stuffed, becoming hollow; exannulate; universal veil as complete or incomplete short limb of membranous to submembranous tissue about 20 - 30 mm from stipe base [white to whitish to orangish white (6A2) at first, becoming pale ashgray to gray to brownish gray (8E2)] or in scattered grayish patches or dark gray-brown (nearly black in exsiccata) bands low on stipe, with color change occurring from uppermost portion downward, sometimes with whitish rather small cupulate portion enclosing base of stipe.

Odor mild or lacking or fungoid or slightly disagreeable (not strong).  Taste mild.

MACROCHEMICAL TESTS: Ammonia soln. - negative on lamellae.  KOH soln. - negative on pileipellis and on lamellae.  Spot test for laccase (syringaldazine) - negative throughout basidiocarp.  Spot test for tyrosinase (paracresol) - positive throughout basidiocarp.  Phenol (also tyrosinase indicator) - negative on pileipellis [obscured because of color?], turning flesh directly chocolate.  Test vouchers: Franco-M. 534, 905, 906; Gómez & Alfaro 24759; Mueller 4642.

PILEIPELLIS: 80 - 160 µm thick overall (145 - 235 µm in material in which sporulation just beginning when dried); suprapellis 5 - 35 µm thick (20 - 60 µm in material in which sporulation just beginning when dried), colorless, with hyphae gelatinized or partially gelatinized; subpellis 75 - 125 µm thick (120 -175 µm in material in which sporulation just beginning when dried), with hyphae partially gelatinized or ungelatinized yellow-brown to orange-brown, with pigment sometimes extending short distance into pileus context; filamentous, undifferentiated hyphae 1.8 - 7.5 µm wide, branching, interwoven, subradially arranged in part, with intracellular pigment sometimes becoming guttulate in 2% KOH; vascular hyphae 1.0 - 11.5 µm wide, locally tangled loosely, common to plentiful, rarely branching, sinuous.  PILEUS CONTEXT: filamentous, undifferentitated hyphae 1.8 - 10.0 µm wide, branching, plentiful, dominating in tissue nearest pileipellis and nearest lamellae, with walls thin to slightly thickened, often in fascicles, interwoven in moderately open lattice; acrophysalides plentiful, dominating in region away from pileipellis and lamellae, clavate to pyriform to subovoid to ovoid to ellipsoid to elongate (subfusiform or narrowly subfusiform), to 136 × 49 µm (mostly under 100 µm long), with walls thin or slightly thickened, sometimes with penultimate hyphal segment partially inflated, sometimes in chains of two; vascular hyphae 1.0 - 15.5 µm wide, branching, infrequent to locally common to locally plentiful, locally in coils and knots.  LAMELLA TRAMA: obscurely bilateral; w_cs = (30-) 55 - 95 (-105) µm; subhymenial base poorly or not differentiated from subhymenium; central stratum containing plentiful intercalary inflated cells [clavate to ellipsoid to subfusiform, up to 80 × 34 µm (mostly under 65 × 25 µm), sometimes with wall slightly thickened at least in apical region]; filamentous, undifferentiated hyphae 1.5 - 10.0 µm wide, branching; diverging, terminal inflated cells not observed; vascular hyphae 2.2 - 15.0 µm wide, sinuous, scarce to locally common.  SUBHYMENIUM: w_st-near = (5-) 15 - 45 (-50) µm; w_st-far = (25-) 35 - 70 µm; pseudoparenchymatous, occasionally locally showing some branching of chains of cells or slightly inflated hyphal segments, with inflated cells (to 35 × 26 µm) in one to three (below bases of longest basidia/-oles) to four or five (below bases of shortest basidia/-oles) layers with larger cells nearest central stratum, with basidia arising from inflated cells or slightly inflated short hyphal segments or occasionally directly from a hypha of the central stratum.  BASIDIA: 45 - 82 × 9.5 - 20 µm thin-walled, but rather commonly with wall up to 0.8 µm thick in apical region, 4- or occasionally 3- or 2-sterigmate, with sterigmata up to 17.5 × 7.5 µm (largest by far in matural in which sporulation just beginning); clamps rare to locally common, somewhat difficult to detect because of thin wall.  UNIVERSAL VEIL: On pileus, exterior surface: often strongly gelatinized or eroded away.  On pileus, interior: filamentous, undifferentiated hyphae 1.5 - 11.5 µm wide, frequently branching, loosely interwoven, often in fascicles, plentiful, partially gelatinized, more common near pileipellis; inflated cells subglobose to ellipsoid to ovoid to clavate to broadly fusiform to narrowly subfusiform, up to 72 × 55 µm, terminal dominating, pale gray to gray to grayish brown to brown to brownish gray, collapsing, with walls thin or up to 0.8 µm thick; vascular hyphae 1.8 - 11.0 µm wide, scattered, slightly more common than on stipe base.  On pileus, adjacent to pileipellis: filamentous, undifferentiated hyphae as in interior, gelatinized; inflated cells smaller than in interior, gelatinized.  On stipe base, exterior surface: somewhat to extensively gelatinized, sometimes eroded away, with inflated cells collapsing, with orange-brown or brown intracellular pigment in some hyphal segments and some inflated cells, dominated (at least locally) by filamentous, undifferentiated hyphae.  On stipe base, interior: similar to interior of pileal warts, but with hyphae somewhat more plentiful; filamentous, undifferentiated hyphae 1.5 - 9.5 µm wide, branching, hyaline, colorless, loosely interwoven, sometimes in fascicles, with walls thin or slightly thickened (0.5^* µm, in those of larger diameter); inflated cells with walls thin or up to 0.5 µm thick, sometimes colorless, otherwised colored as on pileus, subglobose to subovoid to ovoid to ellipsoid to subclavate to elongate, terminal or in short chains, to 70 × 52 (-62) µm, dominant away from inner surface; vascular hyphae 1.0 - 6.0 µm wide, not common; clamps absent or infrequent. On stipe base, inner surface: filamentous, undifferentiated hyphae dominating.  STIPE CONTEXT: longitudinally acrophysalidic; filamentous, undifferentiated hyphae 1.5 - 11.2 µm wide, branching, plentiful, with walls thin or up to 0.8 µm thick; acrophysalides to 375 × 50 µm, but most less than half that length, of nearly cylindric, dominating, with walls thin to 1.2 µm thick, sometimes subtended by partially inflated hyphal segment; vascular hyphae 2.5 - 14.5 µm wide, infrequent or so plentiful as to partially obscure other structures at times, locally in coils and knots branching, with those of largest diameter having slightly thickened walls.

BASIDIOSPORES: [400/17/13] (7.8-) 9.5 - 14.0 (-17.0) × (7.2-) 8.8 - 12.8 (-15.5) µm, (L = (10.2-) 10.3 - 12.1 (-13.0) µm; L' = 11.2 µm; W = (9.5-) 9.6 - 11.5 (-12.2) µm; W' = 10.5 µm; Q = (1.0-) 1.02 - 1.16 (-1.33); Q = 1.05 - 1.11 (-1.15); Q' = 1.07), hyaline, colorless, thin-walled, smooth, inamyloid, globose to subglobose, occasionally broadly ellipsoid, rarely ellipsoid, slightly to distinctly adaxially flattened, sometimes somewhat irregularly shaped; apiculus sublateral, truncate conic to cylindric, to 3.5 µm broad at the base, sometimes appearing splintered; contents monoguttulate; white with or without yellowish cast in deposit.

Ecology: Colombia: Solitary to subgregarious, 2500^* - 3000 m elev. In Q. humboldtii forest (Overbo 2426 & 2507; Franco-M. 534, 905, & 906) or under Q. colombiana Cuatrec. and Q. humboldtii (Singer B 3596).  Costa Rica: Solitary, 1800 - 2880 m. In Quercus forest (Gómez 24759, Singer B 12397) or in Quercus dominated forest (Franco-M. 1104 & 1157; Mueller 4642) or with Q. copeyensis (Franco-M. 1158) or with Q. copeyensis and Q. seemannii (Franco-M. 1153) or with Q. seemannii (Franco-M. 1161) or "in magnolietum" (Gómez 18449).  Honduras: Subgregarious, at 1800 m elev. Under Quercus (Mueller 4127).

DISCUSSION

Amanita inaurata f. americana sensu Singer and possible synonymy are mentioned in Garrido and Bresinsky (1985).  The synonymy proposed was with A. gemmata sensu Guzmán & Varela which is clearly not a member of section Vaginatae.  RET concurs with Tulloss et al. (1992) that the latter taxon can be identified as A. xylinivolva.