Gymnopus quinaultii R.H. Petersen, 2016

Petersen, Ronald H. & Hughes, Karen W., 2016, Micromphale sect. Perforantia (Agaricales, Basidiomycetes); Expansion and phylogenetic placement, MycoKeys 18, pp. 1-122 : 81-86

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Gymnopus quinaultii R.H. Petersen

sp. nov.

9. Gymnopus quinaultii R.H. Petersen sp. nov.


United States, Washington, Grey’s Harbor Co., vic Amanda Park, Forest service Rd. 2140, “Higley’s Swamp," 16.X.1992, coll RHP & KWH, TFB 5886 ( TENN-F-51994).


Lake Quinault and the Quinault River, Washington, the vicinity of the holotype collection.


1) Fruiting on Thuja debris (less on associated Abies and Tsuga needles); 2) rhizomorphs short, stout, arising and terminating in small black pads; 3) stipe fuscous brown-black, vestured, especially downward; 4) pileal hairs often ornamented with annular rings; 5) pileipellis constructed of incrusted hyphae, and hyphae with gelatinizing walls; 6) cheilocystidia not observed.

The description below is based on dried material only.

Description. Basidiomata (Fig. 65A View Figure 65 ) marasmioid, diminutive. Pileus 3-15 mm broad, convex to plano-convex, matt, very short-striate on downturned margin; disc now near "sayal brown" 6C5, outward now dull cinnamon buff, near “avellaneous” 7B3 to "vinaceous buff" 9B2. Lamellae (Fig. 65A View Figure 65 ) adnate to adnexed, close to subdistant, seceding somewhat upon drying and then appearing pseudocollariate, subventricose (- 1.2 mm broad), thickish, with no anastomoses; total lamellae = 30-32; through lamellae = 11-14, now concolorous with pileus, bleeding slightly from dark brown stipe apex; lamellulae short, in 1-2 ranks; lamellar trama under magnification (40 ×) appearing glassy (probably gelatinized). Stipe 15-30 × 0.7-1.2 mm, subinsititious, terete, equal, hollow, minutely vestured upward (35 ×), downward becoming pruinose to minutely hispid, upward “cinnamon” 6B5 to "orange cinnamon" 7B6, soon brown and downward "fuscous black" 6F4 to "chaetura black" 2F3 (not totally black anywhere), remaining darker than lamellae through attachment to pileus flesh; medulla off-white. Rhizomorphs (Fig. 65A View Figure 65 ) apparently common on Thuja branchlets (incidental on Abies needles), - 10 mm × 0.3-0.8 mm (relatively stout for length), arising from a small black pad (and terminating similarly on adjacent needles), commonly branched (usually short, spur branches), colonizing adjacent needles; resupinate black hyphae individual, meandering over substrate surface. Taste and odor not recorded.

Habitat and phenology.

Fruiting on dead needles of Thuja plicata and Abies grandis ; Autumn.

Pileipellis composed of the following elements: 1) pileal hairs (Fig. 66 View Figure 66 ) -100 × 3-4.5 µm, erect, usually more or less straight, firm-walled, often with basal clamp connection, often weakly ornamented, especially in annular rings (Fig. 66D View Figure 66 ); 2) repent, unoriented, interwoven hyphae 3.5-8 µm diam, thin-walled but wall gelatinizing to 2-3 µm thick (Fig. 67C, D View Figure 67 ), with vague outer wall, obscurely clamped; and 3) weakly to strongly encrusted hyphae (Fig. 67A, B View Figure 67 ) 4.5-8 µm diam, thin-walled but semi- gelatinizing; incrustation in scabs and/or vague stripes, with strong but rough profile calluses; narrower hyphae encrusted as though with many minute crystals (not coarse scabs). Lamellar trama loosely interwoven; hyphae 3-5.5 µm diam, firm-walled, clamped. Pleurocystidia (Fig. 68 View Figure 68 ) common, 28-34 × 6-8 µm, fusiform, conspicuously clamped; contents homogeneous or partitioned. Basidioles (Fig. 69A View Figure 69 ) clavate; basidia (Fig. 69B-D View Figure 69 ) (25-)30-33(-37) × 6.5-9 µm, clavate, subtly subcapitulate, 4-sterigmate, clamped. Basidiospores (Fig. 65B View Figure 65 ) (6.5-)7.5-9(-9.5) × (3.5-)4-4.5 µm (Q = 1.63-2.50; Qm = 1.99; Lm = 7.82 µm), plump-ellipsoid, marasmioid (somewhat tapered proximally), flattened adaxially, smooth, thin-walled, inamyloid; contents vaguely univacuolate (PhC). Cheilocystidia not observed. Stipe medullary hyphae strictly parallel, perhaps coherent, 2-9 µm diam, firm- to thick-walled (wall - 1.0 µm thick, hyaline), conspicuously clamped. Stipe cortical hyphae 4-7 µm diam, strictly parallel, minutely roughened, thick-walled (wall -2 µm thick), obscurely clamped; stipe vesture setoid, hardly gathered into synnemata but usually densely scattered. Caulocystidia (Fig. 65C View Figure 65 , 70 View Figure 70 ) -180 × 3.5-7 µm, oc curring as side branches of stipe surface hyphae, irregularly rooted, often gnarled at base, tapering distally to rounded apex, thick-walled (wall 1.5-3 µm thick, often occluding cell lumen, dull yellow-ochre, highly refringent), yellowish (PhC), occasionally internally clamped and/or secondarily septate.


G. quinaultii clearly belongs in sect. Perforantia . The vestured stipe is not black but fuscous brown. Spores are somewhat large for sect. Perforantia , and host association ( Thuja / Abies ) is different (not spruce/fir needles).

Based on habitat on Thuja debris, an ancillary study was made of Collybia thujina Kauffman ( MICH!), which immediately led to examination of material of Marasmius filopes Peck ( NYS!) and Collybia piceina Kauffman ( MICH!). Prior treatments had been published by Hesler (1959), Gilliam (1976), Redhead (1980) and Desjardin (1989). Basidiomata of all correctly identified collections were significantly smaller and more slender than those of G. quinaultii , and pileipellis organization was of a well-developed Rameales -structure, not similar to that in G. quinaultii . Desjardin (1989) agreed with Redhead that M. filopes , C. piceina and C. kauffmanii were taxonomic synonyms, all correctly placed in Marasmiellus by Redhead. I agree with this assessment, leaving G. quinaultii as a separate taxon.

Specimens examined.

Canada, British Columbia, vic. Whistler, Paradise Valley between Whistler and Squamish, 49°50'35" N, 123°09'25"W, 6.X.1990, coll RHP & LWH, TFB 3400/4 ( TENN-F-49650) GoogleMaps . United States, Washington, Grey’s Harbor Co., vic Amanda Park, Forest service Rd. 2140, “Higley’s swamp," 16.X.1992, coll RHP & KWH, TFB 5886 ( TENN-F-51994; holotype) .