Observation 81846: Agaricus smithii Kerrigan
When: 2011-10-29
Herbarium specimen reported

Notes: Habitat: in sandy soils ~400-500 meters inland from the shore, in close proximity to Shore Pine (Pinus contorta var. contorta) and Scotch Broom (Cytisus scoparius)

Habit: solitary or in scattered groups of 3-4, not particularly abundant

Odor: strong, almondy

Taste: pleasant, sweet

Pileus: dry, smooth, hemispherical when young, becoming convex to broadly convex or nearly planar in age, older specimens frequently split at margin (especially in dry conditions), appressed-fibrillose becoming minutely appressed-squamulose, background pallid becoming yellowish, flesh white and unchanging.

Lamellae: free, close, pinkish white when young, becoming gray and finally chocolate brown. margins conspicuously darker upon drying.

Stipe: bulbous, often abruptly so esp. in older/larger fruiting bodies, tapering slightly toward the apex, markedly lighter above, tawny below with a layer of thin brown fibrils, flesh white, yellowing at base, unchanging elsewhere, drying yellowish to yellowish orange, stuffed-hollow to hollow in age, base with many white mycelial strands.

Veil: PV white, soon developing eventually broadly-spaced radial fissures at the margin which are concolorous with the cap, cottony, thick (~1-2mm), subapical, pendant, often splitting at equal intervals along these radial fissures to form a stellate pattern leaving four or more equidistant “flaps” of PV tissue attached, drying yellowish-orange.

All tissues readily yellowing in KOH.


Pileipellis: a cutis of long, interwoven, occasionally branched, septate, clavate hyphae ranging from 5 to 15μm in thickness. clamps not observed.

Cystidia: Thiers’ description mentions “basidiole-like or globose to ovoid or irregular” cheilocystidia which are “scattered in clumps.” The structures shown in the microphotos of the gill edge seem to confirm that feature, but these were only visible when the edge was slightly crushed as none were long enough to jut out beyond the hymenium. Had I not already suspected A. smithii (courtesy of Dennis’ suggestion) and specifically gone in search of these structures, I would have listed this as “cystidia absent.”

Basidia:

Spores: Ellipsoid to subfusiform to amygdaliform, smooth, thick-walled, w/ guttular contents, apiculus usually prominent and seemingly bright yellow in KOH.

8-11μm x 4.5-6μm (x = 9.2μm x 5.1μm, m=20, s=1)

8×5
9×5
9×5
10.5×5
11×5
11×4.5
8×5
9×5
7×5
9.5×5.5
9×5.5
10×5
9×5
9×6
9.5×5.5
11×6
9×5
9×5
9.5×4.5
8.5×4.5

Species Lists

Images

180823
188490
1000x KOH – cheilocystidia
188491
1000x KOH – cheilocystidia
188492
1000x KOH – cheilocystidia
188493
1000x KOH – spores
188496
1000x KOH – spores (yellowing apiculus more visible in this photo)
188497
400x KOH – pileipellis

Proposed Names

58% (1)
Eye3 Eyes3
Used references: Dr. Dennis Desjardin & Thiers’ Agaricales of California
29% (1)
Recognized by sight

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Eye3 = Observer’s choice
Eyes3 = Current consensus

Comments

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This
By: Danny Newman (myxomop)
2011-12-10 01:36:53 CST (-0500)

appears to be a pretty flawless match for A. smithii with just two notable exceptions (so far).

1. No description seems to make any mention of this stellate rupturing of the veil despite every specimen I’ve seen possessing this trait. The “cog-wheel” pattern around the outer edges of the unbroken PV is mentioned, but that’s as close as any description gets.

2. Not once, in this collection or any other, have I observed yellow basal mycelium. Stark white every time.

Created: 2011-11-09 22:53:59 CDT (-0400)
Last modified: 2011-12-16 03:22:39 CST (-0500)
Viewed: 210 times, last viewed: 2016-11-22 14:45:52 CST (-0500)
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