Gymnopus pinophilus 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 : 61-67

6. Gymnopus pinophilus R.H. Petersen sp. nov.

Holotype.

United States, North Carolina, Macon Co., vic. Highlands, Blue Valley Campground, N35°00'45.23", W83°09'29.33", 11.VIII.2014, coll KWH, TFB 14511 ( TENN-F-69206).

Etymology.

pino- = referring to the genus Pinus ; -phil = to love, referring to habitat on the needles of Pinus .

Diagnosis.

1) Fruiting habit on needles of Pinus strobus in eastern North America; 2) pileipellis structure including occasional diverticulate hyphae and broom cell-like hyphal termini; 3) cheilocystidia of the siccus -type; 4) basidiomata with long, slender stipes and small pilei; 5) stipe glabrous-shining; 6) rhizomorphs hair-like, black, independent of basidiomata.

Description.

Basidiomata (Fig. 47 ) slender, with long stipe and small pileus. Pileus 3-9(-12) mm broad, convex becoming shallowly convex, sometimes centrally depressed, matt, pebbled, subtly sulcate-striate; disc "fawn color" 7C5, 6E7, "vinaceous fawn" 8B4, "ocher red" 9C6 to "brick red" 8D8, outward “avellaneous” 7B3, 6D4-6, "vinaceous fawn" 8B4, "vinaceous buff" 9B2 "buff pink" 7A4, drying nut brown ("tawny olive" 5C5). Lamellae adnexed to adnate, sometimes pseudocollariate (especially in drying), thickish, not ventricose, with little evidence of anastomosis, off-white to "tilleul buff" 7B2, 6C3-4; lamellulae always very short, hardly ventricose. Stipe 27-45(-60) × 0.4-1 mm, stiff, terete, equal, not vestured, glabrous and often shining, insititious, apically concolorous with lamellae ("tilleul buff" 7B2 to "army brown" 8D5), soon "clove brown" 6F5 to black and remaining so, stuffed; stipe medulla white. Rhizomorphs (Fig. 47 ) -18 × 0.2-0.3 mm, hair-like, curly, black, usually unbranched, arising separately from basidiomata. Odor negligible; taste negligible.

Habitat and phenology.

Gregarious on dead needles of Pinus strobus in eastern North America; summer.

Pileipellis involved in a heterogeneous slime matrix, composed of the following elements: 1) repent hyphae radially oriented, 2.5-6 µm diam, firm- to thick-walled (wall -0.7 µm thick, hyaline), firm-walled with a very thin mucoid sheath, conspicuously clamped, weakly to strongly encrusted, with encrustation appearing as vague, subtle stripes or rings with flake-like profile calluses (Fig. 48A ) (lying on the thin mucoid sheath); 2) repent hyphae 4-7.5 µm diam, with gelatinized wall (Fig. 48B ) (wall -1.5 µm thick, with weak encrustation); 3) occasional repent hyphae 3.5-5.5 µm diam, firm-walled, clamped, diverticulate; diverticula 2-6 × 1-1.5 µm (Fig. 48C ), usually dichotomous, not refringent; and 4) common broom cell-like cells, stalked, arbuscular (stalked without distal inflated portion), branched 1-2 times, surmounted by setulae; setulae digitate, often knobby, usually dichotomous, -6 × 1-1.5 µm, sometimes subrefringent (PhC); broom cell-like structures (Fig. 49 ) easily gelatinizing from base and often visible only as setulae (Fig. 49A,D ). Pileus and lamellar tramae loosely interwoven, with heterogeneous slime matrix. Hymenophore (in KOH) involved in a heterogeneous mucoid matrix with copious debris (collapsed spores, bits of effete basidia, etc.). Pleurocystidia (Fig. 50A-D ) 24-32 × 5.5-8 µm, fusiform, conspicuously clamped; contents homogeneous, often with poorly partitioned contents. Basidioles clavate; basidia (Fig. 50E-H ) 23-31 × 5.5-7 µm, clavate, clamped, 4-sterigmate; contents multigranular. Basidiospores (Fig. 51 ) probably dimorphic: 1) (3.5-)4-6(-6.5) × (2.5-)3-4(-4.5) µm (Q = 1.11-2.17; Qm = 1.57; Lm = 5.15 µm); 2) (5.0-)6-8(-8.5) × (2.5-)3-4.5 µm (Q = 1.38-2.40; Qm = 1.96; Lm = 7.19 µm), broadly ellipsoid, subcylindric to elongate-lacryiform, hardly flattened adaxially, thin-walled, smooth; contents homogeneous to a few scattered minute, refringent granules. Lamellar edge involved with heterogeneous mucoid matrix; cheilocystidia (Fig. 52 ) 20-34 × 6-9 µm, scattered to common, similar to pileipellis element, broom cell-like, easily gelatinizing, stalked (stalk 2.5-3 µm diam), arbuscular, terminating in a very complex tuft of setulae; setulae -8 × 1-1.5 µm broad), refringent (PhC), digitate, often dichotomous. Outer stipe medullary hyphae involved in a slime matrix, skeletal-generative, 5-12 µm diam, thick-walled (wall -2.0 µm thick), conspicuously clamped, occasionally producing flagelliform hyphal tips -250 × 1-1.5 µm diam, thick-walled near origin, thin-walled apically; stipe cortex hyphae 4-7 µm diam, thick-walled (wall occluding cell lumen), strongly pigmented, non-dextrinoid; surface hyphae minutely roughened. Caulocystidia not observed.

Commentary.

Desjardin (1989) and Gordon (1994) treated G. pinophilus as an unnamed subset of Ma. androsaceus . The latter was perceived as fruiting on three sub strata, hardwood leaves, needles of Picea / Abies , and needles of Pinus . Gordon and Petersen (1997) understood that M. androsaceus s.l. in eastern North America could be divided into three sexually interINcompatible groups, one of which (mating group III) was represented by only a single collection (TFB 5627 TENN-F-53488 from Idaho). With subsequent collecting and DNA sequence production, this collection was determined as G. pinophilus . Mata et al. (2007) showed that Marasmius sect. Androsacei (represented by M. androsaceus ) was actually embedded within Gymnopus , and Noordeloos and Antonín (2008) formally transferred the section as Gymnopus sect. Androsacei . Furthermore, Desjardin (1990) and Desjardin and Horak (1997) reported considerable morphological and phenological variation within the North Temperate Androsacei , in part by circumstantial evidence, based on the data above. Present phylogenetic analyses now show that the small alliance of G. pinophilus and G. ponderosae ( Gordon’s mating group III) is more closely related to the Mi. perforans complex than to the Ma. androsacei complex.

Observation on TFB 14097 ( TENN-F-67846) revealed two sets of dimensions of spores, and TFB 10459 showed that these spores are formed by basidia in the same hymenium - thus spores must be judged as dimorphic. One cause for this might be 2- versus 1-nucleate condition of individual spores, but all seem to be produced by 4-sterigmate basidia.

Observations of pileipellis of TFB 10459 showed that broom cell-like hyphal termini are ephemeral - apparently they wash or gelatinize away, so when they were absent from some pilei of various collections, the strongly ornamented repent hyphae remained.

Recently, TFB 14097 was established in dikaryron and monokaryon cultures and a self-cross was performed (see Gordon and Petersen 1997 for methods). From an assay of 20 putative single-basidiospore isolates (SBIs), 12 clampless putative monokaryons were selected and paired in all combinations. As expected, a tetrapolar mating system was revealed. A1B1 = 5*, 6; A2B2 = 1*, 3, 4, 8; A2B1 = 2*, 7, 9, 11, 12; A1B2 not represented in the sample (* indicates a tester strain). Most growth of donors was submerged (except for structures noted below). Most pairings exhibited very subtle “barrage” or “flat” contact zones, most easily envisioned with the naked eye against back-lighting. Barrage = somewhat congested growth in “mustaches” (not within contact zone). Flat = slightly congested hyphae on both sides of a lightly overgrown crevasse.

On malt extract (Difco, 15 g/L) agar (Difco, Bacto, 20g/L) most SBIs produced: 1) pure white spherical hyphal masses (<1- 2 mm diam; appearing as minute “snowballs”). These structures are narrowly attached to the agar-surface mycelium and are composed of loosely interwoven hyphae with a mucoid medulla, pure white inside and out, easily crushed (like a cotton ball); and 2) minute ganglia of hyphae scattered over agar surface in mucoid matrix. SBIs include two hyphal types: 1) 4-6.5 µm diam, thin-walled, frequently septate, hardly inflated; and 2) roughly arbuscular, 1.5-2.5 µm diam, thin-walled, as though a ramealis structure but with branches longer, apparently opposite or sub-opposite.

Specimens examined.

Canada, Nova Scotia, Kejimkujik National Park, Grafton Lake Loop Trail, 5.VIII.1992, coll S.A. Gordon, TFB 5034 ( TENN-F-53487). United States, New York, Franklin Co., Malone, Franklin Academy High School nature trail, 14.VII.1992, coll Scott Gordon, TFB 4975 ( TENN-F-53478). North Carolina, Haywood Co., GSMNP, Cataloochee Cove, Schoolhouse area, N35°37'43.93", W83°06'44.18", 5.IX.1992, coll RHP, TFB 5547 ( TENN-F-52480); same location, 9.IX.1987, coll DE Desjardin, DED 4491 ( TENN-F-54665); Jackson Co., vic. Cashiers, Panthertown Valley, N35°09'34.63", W83°00'35.75", 24.VI.1992, coll. JE Johnson, TFB 6311 ( TENN-F-53128); Macon Co., vic. Highlands, Cliffside Lake, end of road, N34°04.749', W83°14.150', 4.VIII.2012, coll. KWH, TFB 14097 ( TENN-F-67846); Cliffside Lake Campground, N35°04'44.92", W83°14'12.90", 3.IX.1986, coll D.E. Desjardin. DED 4107 ( TENN-F-54643; SFSU); Highlands, Highlands Biological Station, N35°03'09.72", W83°11'19.98", 9.VIII.1966, coll LR Hesler, LRH 29279 ( TENN-F-29279); vic. Highlands, Bull Pen Rd., Ellicott Rock Wilderness trailhead, N35°01.010', W83°08.190', 20.VII.2011, coll RHP, TFB 13913 ( TENN-F-65808); Horse Cove, Walking Stick Rd., "Double Bridges," N35°00.983', W83°09.619 ", 31.VII.2012, coll RHP, TFB 14059 ( TENN-F-67804); Bull Pen Rd., Ellicott Rock Wilderness trailhead, N35°01.010', W83°08.190', 20.VII.2011, coll RHP, TFB 13913 ( TENN-F-65808); Nantahala Nat. For., Blue Valley Campground, N35°00'45.23", W83°09'29.33", 11.VIII.2014, coll KWH, TFB 14511 ( TENN-F-69206; holotype); vic. Franklin, Standing Indian Campground, 19.VII.1994, coll DBG Nichol, TFB 7629 ( TENN-F-53659). South Carolina, Oconee Co., Burrell’s Ford campground, N34°58.408', W83°06.726, 12.VIII.2014, coll Highlands Biol. Station class, TFB 14517 ( TENN-F-69212).

Figures

Figure 47. Gymnopus pinophilus. Basidiomata on needles of Pinus strobus. Standard bars = 20 mm. Above: TFB 14511. Below: TFB 14059 (TENN-F- 67804).

Figure 48. Gymnopus pinophilus. Pileipellis elements. A Encrusted hyphae showing crust material in slime sheath B Hyphae with gelatinized walls C Diverticulate hypha showing dichotomous diverticula. Standard bars = 10 µm. DED 4491 (TENN-F- 54665).

Figure 49. Gymnopus pinophilus. Broom cell-like hyphal termini of pileipellis. A Diverticula in slime matrix B, C Individual elements D Gelatinizing broom cell-like termini. Standard bars = 10 µm. DED 4491 (TENN-F- 54655).

Figure 50. Gymnopus pinophilus. Hymenial elements. A-D Pleurocystidia E-H Basidia. Standard bars = 10 µm. DED 4491 (TENN-F- 54665).

Figure 51. Gymnopus pinophilus. Basidiospores. Standard bars = 5 µm. A = TFB 14097. B = TFB 10459 (TENN-F- 67804).

Figure 52. Gymnopus pinophilus. Cheilocystidia. A Cluster of two cheilocystidia B-H Individual cheilocystidia. Standard bars = 10 µm. TFB 7234 (TENN-F- 53553).