Observation 96716: Agaricus pequinii (Boud.) Singer

Cap: Highly reflexed as if folded upward in half. 4-1/2 inches at widest, 2" at narrowest, surface dry, soft, rubbery, cream color with brown patches, appearing partially translucent in some areas. Margin free of gills about 1/16" and folded in and out.Gills: Dark brown, very close, adnexed, covered in small particles of sand, edge appears to glow gold in some photosStalk: 1-1/4" long with 1-1/4" bulb, total stalk and bulb length 2-1/2".Stalk covered with brown scales, darker at top, flaring slightly at gills. Annulus at top of bulb, white, papery thin with ragged edges, one piece 1/2" long. Bulb pointed w/o apparent mycelium.Strong mushroomy odor. Stipe turns bright meat-red instantly when cut, then dull brown. Context color unchanging when cut. Context and cap unchanging in KOH, Ammonia, and FeSO4. Alkalis prevented red reaction on cut stipe.The following observations (with herbarium specimens)from same location: http://mushroomobserver.org/79686?q=1XDLN (2011-10-16)http://mushroomobserver.org/112572?q=1XDLN (2012-10-06)http://mushroomobserver.org/113628?q=1XDLN (2012-10-16)http://mushroomobserver.org/116165?q=1XDLN (2012-11-08)

Species Lists


quickly meat-red when cut, then dull brown
highly reflexed cap
pale highlight on gill edges
cap dry, white with brown stains
globose spores
red reaction absent from bulb

Proposed Names

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Used references: Agaricus of North American by Rick Kerrigan p. 119

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Stipe with red streaking.
By: Daniel B. Wheeler (Tuberale)
2012-06-09 17:21:49 AST (-0400)

Very unusual for Agaricus. Pretty, in its own way. Thanks for the sequencing, Rick.

By: Rick Kerrigan (rwkerrigan)
2012-06-09 12:38:24 AST (-0400)

Nice specimen, Martin, and nice photos of the localized red staining reaction. Folks, in the western hemisphere this species is known only from Martin’s patch. I got a nice ITS DNA sequence from the last fruiting.

Created: 2012-06-08 20:48:34 AST (-0400)
Last modified: 2016-12-12 18:34:11 AST (-0400)
Viewed: 184 times, last viewed: 2017-12-25 01:27:39 AST (-0400)
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