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Summary: Section Xanthodermatei. Agaricus hondensis is distinguished by 1) large size, 2) an often pink-tinged, fibrillose cap that often darkens when old, 3) pale pinkish to pinkish gray gills at first, 4) a thick, rather stiff, felty ring, 5) bald stem, 6) phenol odor when the base of the stem is broken open, 7) usually pale yellowish staining in the base of the stem, 8) yellow staining of the cap in KOH, and 9) woodland habitat. It is possible that some of the Pacific Northwest material that has been called Agaricus hondensis is Agaricus subrufescentoides. Synonyms include A. hillii, and A. mcmurphyi according to Smith(47) and Kerrigan(3). Smith(47) also includes A. bivelatoides and A. glaber but Kerrigan(3) disagrees on the former and is not sure about the latter.
The holotype is from CA. Agaricus hondensis is "a characteristic if not superabundant fungus of the Pacific North American temperate forests", (Kerrigan(2)). It is indicated for BC and CA in Smith(15), for WA and OR by Isaacs(1), for ID (Andrew Parker, pers. comm.), and for AB by Schalkwijk-Barendsen(1). There is DNA support for material in WA (D. Miller, pers. comm. regarding the Buck McAdoo illustration of a whitish capped collection).
Cap: 6-15(20)cm convex becoming flat; whitish or with pale pinkish brown to pinkish gray to fawn-colored flattened fibrils or fine fibrillose scales (at least at center), the fibrils often darkening when old to brown, reddish brown, or reddish gray, but in one northern form darker brown from the beginning; dry, smooth, (Arora), 8-15cm broad, hemispheric becoming broadly convex then flat; pallid to buff, sometimes darker brown, especially when old, background whitish; dry, bald or appressed fibrillose-squamulose [fibrillose - fine-scaly] or subareolate [somewhat cracked like dried mud], (Kerrigan(1)), varies from cream to deep vinaceous brown (Kerrigan(2))
Flesh: thick; "white, unchanging or staining pale yellowish when bruised, then often slowly discoloring pinkish", flesh in extreme base of stem usually bruising pale yellowish, (Arora), up to 1.5cm thick; white, unchanging, in stem lustrous, white, unchanging or becoming somewhat yellow in lower part, (Kerrigan(1)), markedly solid (Trudell)
Gills: free at maturity, close; pale pinkish to pinkish gray becoming brown, then chocolate brown or darker, (Arora), free, close, up to 1cm broad; pinkish at first, becoming dull pinkish and finally dark blackish brown, (Kerrigan(1)), grayish pink, becoming purplish brown, (Lincoff), free, close to crowded, narrow; "pink to pale grayish lilac, becoming more or less deep reddish brown", (Ammirati), white in buttons, then pinkish, finally lilac-gray to reddish brown or chocolate brown, (Chariton), grayish to pale pinkish when young (Trudell)
Stem: 7-20cm x 1-2.5cm but with a thicker or more bulbous base, firm; "white or discoloring dingy pinkish or brownish in age or after handling"; smooth, naked, (Arora), 12-20cm x 1-1.5cm, 2-3cm wide in lower part, stuffed-hollow, "base fairly shallowly rooted even though often developing under deep litter"; white, unchanging; "smooth, or with some fibers subtending annulus", (Kerrigan(1)), usually with an abrupt bulbous base (Ammirati)
Veil: membranous, white, forming a thick, felt-like, superior ring on stem, ring skirt-like but often flaring outward instead of collapsing against stem, (Arora), veils forming a thick, pendant, subapical, white ring, rather stiff, flaring broadly, tending not to collapse until very old, smooth upper surface, (Kerrigan(1)), membranous, moderately thick, apical on stem, upper surface of ring white and striate, "lower surface typically with loose dark pink to grayish vinaceous cottony fibrillose patches, or merely loosely white-fibrillose", universal veil lacking, (Ammirati)
Odor: crushed flesh mild or faintly phenolic but usually distinctly phenolic in base of stem when crushed, (Arora), phenolic or often indistinct, usually strongly phenolic in base, (Kerrigan(1))
Microscopic spores: spores 4.5-6 x 3-4 microns, elliptic, smooth, (Arora), spores (3.4)4.7-5.7(6.0) x (3.0)3.3-3.5(5.3) microns, elliptic to elongate, dark brown, hilar appendix somewhat prominent, germ pore not evident; basidia 4-spored, 22-25 x 6 microns, cylindroclavate to clavate, sterigmata 3-4 microns long; cheilocystidia 10-15 x 10-15 microns, nearly spherical, or possibly also basidiole-like and about 17 x 7.5 microns, uncommon, gill margin primarily composed of narrow hyphae oriented parallel to margin, almost sterile, (Kerrigan(1)), spores (5.1)5.8-7.3(8.8) x 3.7-4.4 microns, broadly elliptic, slightly inequilateral in side view, smooth, thick-walled, without germ pore; pleurocystidia lacking, cheilocystidia 18.3-25.6 x 7.3-11.0 microns, sac-like to clavate, colorless to pale yellowish brown; clamp connections not seen, (Ammirati), spores of type 5.5-6.5(7) x 3.5-4(4.5) microns, but the large spores are unusual and the majority are 5.6-6 x 3.5 microns; cheilocystidia very scattered to clustered saccate, often difficult to locate because of their sporadic occurrence and because they often do not project beyond the basidia, (Smith(47))
Spore deposit: chocolate brown (Arora)
Habitat / Range
single or in groups, troops, or fairy rings in woods on ground, "particularly where there are thick accumulations of fallen twigs and other debris", (Arora), in arcs, subcespitose [more or less in tufts], gregarious, or single, under conifers in needle duff or under brush (Rubus, Holodiscus) in leaves, (Isaacs), gregarious in litter of Sequoia, Pinus (pine), Quercus (oak), rarely Cupressus (cypress) and other trees, usually in deep woods, (Kerrigan(1) for California), low elevation, conifer duff (Chariton), one of the relatively few Agaricus species found under redwood, in California also occasionally found with Cupressus macrocarpa (Monterey cypress) and C. abramsii (Santa Cruz cypress), but north of California occurs with other conifers and may occasionally be found under hardwoods, (Kerrigan(2))
Agaricus subrufescentoides can be visually similar to A. hondensis when the latter is brown - A. subrufescentoides "may be less robust, sometimes approaching a small, even gracile stature, and has longer and broader spores", (Kerrigan(3)). Agaricus moelleri group lacks the pinkish tints and markedly solid flesh of A. hondensis, and the flesh in the extreme base of the stem stains a brighter yellow when cut or crushed, (Trudell). Agaricus campestris and Agaricus bisporus are somewhat similar, but A. hondensis has a prominent ring and an unpleasant odor when the flesh of the stem base is crushed. Agaricus ''crassistipus'' has flesh that turns orange to wine color with nitric acid or alpha naphthol, (bicolored flesh, first yellow then wine-colored), a stem that is short for the breadth of the cap and massively club-shaped, a ring that is recumbent never flaring, and gills that are grayish then reddish brown. Agaricus haemorrhoidarius stains red and has a pleasant odor. Agaricus silvicola is similar if pallid, but A. silvicola has an almond odor. Agaricus californicus (from CA) is smaller with gray-brown fibrils on the inrolled cap. See also SIMILAR section of Agaricus subrufescens and Agaricus subrutilescens.
Recommended citation: Author, Date. Page title. In Klinkenberg, Brian. (Editor) 2020. E-Flora BC:
Electronic Atlas of the Plants of British Columbia [eflora.bc.ca]. Lab for
Advanced Spatial Analysis, Department of Geography, University of British
Columbia, Vancouver. [Accessed:
2023-03-31 9:15:51 AM
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