Gymnopus foliiphilus var. costaricensis R.H. Petersen & J.L. Mata, 2016

Petersen, Ronald H. & Hughes, Karen W., 2016, Micromphale sect. Perforantia (Agaricales, Basidiomycetes); Expansion and phylogenetic placement, MycoKeys 18, pp. 1-122 : 27-30

2A. Gymnopus foliiphilus var. costaricensis R.H. Petersen & J.L. Mata var. nov.

Holotype.

Costa Rica, Prov. San José, km 68 on PanAmerica Highway, "Finca Jaular," N9°39.597', W83°52.115'. 29.VI.2000, coll. RHP, TFB 9750 ( TENN-F-58651).

Diagnosis.

Similar to Gymnopus foliiphilus , but differing as follows: 1) pileus darker at all ages, smooth (not pebbled), not convex when young nor everted in age; 2) lamellae more numerous and lamellulae in two ranks; 3) lamellar attachment adnexed to adnate (not pseudocollariate); 4) stipe black or bicolored; 5) stipe insertion subinsititious (not insititious); 6) outer pileipellis hyphae often significantly encrusted (not smooth or with flakes).

Description.

Basidiomata (Fig. 17A ) diminutive, gymnopoid. Pileus 6-14 mm broad, appearing applanate throughout ontogeny but with downturned margin, outward vaguely sulcate-striate, always very thin-fleshed, smooth (but not glabrous), matt (but not velutinous, etc.), dark brown when young ("amber brown" 6D8, "mummy brown" 6F8, "Natal brown" 8E6, "bone brown" 7F8), fading somewhat by maturity ( “tawny” 6C6, "wood brown" 7C4, "tawny olive" 5C5), essentially unicolorous (but occasionally with a suggestion of a paler central disc). Lamellae (Fig. 17B ) (dried) appearing adnate to adnexed but not pseudocollariate, shallow (-1 mm deep), total lamellae = 30-37, through lamellae = 12-15, "sulphur yellow" 1A2 to " pale ochraceous buff" 4A2, now (dried) near "ochraceous buff" 5A5 to "light ochraceous buff" 5A4 with no evidence of necropigment. Lamellulae in two ranks. Stipe 13-30(-40) × 0.6-1(-1.5) mm, terete, equal, twisted and compressed upon drying, lightly stuffed to hollow, vestured throughout, from minutely flocculose (40 ×) to barbed but not consistently located - sometimes flocculose vesture apical, sometimes both apical and mid-section and alternating with barbed texture; color never black, often bicolorous, upward concolorous with lamellae, soon downward darker, “tawny” 6C6, finally dull fuscous ( “drab” 6D3, "hair brown" 6E3, "citrine drab" 4D5); insertion insititious to subinsititious (very small basal pad - hardly noticeable). Rhizomorphs (Fig. 17A ) sparse, slender, meandering over leaf surface before becoming erect, unbranched, never more than 10 mm long. Odor faint of cabbage, stronger with age; taste not recorded.

Habitat and phenology.

Fruiting on sclerophyllous leaves (perhaps Quercus ) at mid- to high-elevation; early summer.

Pileipellis an intricately interwoven layer of thin-walled, conspicuously clamped hyphae in a heterogeneous matrix of slime (including copious debris), composed of: 1) hyphae 5-15 µm diam (Fig. 18A, B ), firm-walled with thin slime sheath with flake-like crust material riding on outside of sheath; 2) hyphae 6-14 µm diam, firm-walled, producing variable small lobes or outgrowths (Figs 17E , 18C-J ), occasionally proliferating into ribbon-like extensions (Fig. 18K, L ); and 3) occasional strongly encrusted hyphae present; hyphae 4-7 µm diam, encrustation in significant scabs sometimes suggesting stripes, with minimal profile calluses. Lamellar trama loosely interwoven; hyphae 2.5-3.5 µm diam, firm-walled, long-celled, conspicuously clamped (often medallion). Pleurocystidia (Figs 17C , 19A-D ) 17-24 × 6.5-8 µm, fusiform, conspicuously clamped; contents homogeneous. Basidioles clavate; basidia (Figs 17D , 19E-H ) 18-22 × 7-8, broadly clavate, clamped, 4-sterigmate. Small clots of subgelatinous material in hymenium (scattered, evidenced by copious “sludge” and/or debris); effete basidia and pleurocystidia evacuating contents but retaining uncollapsed walls ( “husking”). Basidiospores (Fig. 17F ) (6-)6.5-8 × 3-4 µm (Q = 1.75-2.67; Qm = 2.11; Lm = 7.20 µm), gymnopoid (not tapered proximally), smooth, thin-walled, inamyloid. Cheilocystidia (Fig. 20 ) 23-29 × 5-9 µm, clavate, basidioid, usually slightly subcapitulate. Stipe medullary hyphae 3-17 µm diam, strictly parallel, perhaps adherent (shearing in plates and with copious floating debris), hyaline, firm- to thick-walled (wall -1.0 µm thick), obscurely clamped, with occasional constricted lobes. Caulocystidia from upper stipe (Fig. 21A ) sub-hyaline (pale champagne color in mass, refringent PhC), gnarled (not straight/setoid), thick-walled (wall -2 µm thick), usually clamped internally, gathered into “plaques” (which appears as floccules at 40 ×). Caulocystidia from flocculose lower stipe (Fig. 21B ) -110 µm long, thick-walled (wall -2 µm thick, yellow-refringent; cytoplasm hyaline), usually lobed or branched at base, 7-12 µm broad.

Commentary.

Smooth pileus surface and encrusted pileipellis hyphae are suggestive of Gymnopus sect. Vestipedes , but obvious slime matrix points to sect. Perforantia . The vestured stipe also might point toward G. perforans or sect. Vestipedes (not toward Gymnopus sect. Androsaceus s.s.).

Traditionally, G. perforans has been accepted as quite variable in substrate. ITS phylogeny indicates separation into several species, with G. perforans s.s. limited to conifer needles (usually Picea / Abies ), with segregants on dead deciduous leaves ( G. foliiphilus ), or needles of Pinus strobus ( G. pinophilus ) or P. ponderosa ( G. ponderosae ). Collection TFB 9750 TENN-F-58651 matches this complex micromorphologically, and especially G. foliiphilus in substrate.

Specimens examined.

Costa Rica, Prov. Heredia, County Barva, District San José de la Montaña, viz. Sacramento , 25.VIII.2014, JLM 2238 ( USAM); Prov. San José, km 68 on PanAmerica Highway , Finca Jaular , N9°39.597', W83°52.115'. 29.VI.2000, coll. RHP, TFB 9750 ( TENN-F-58651; holotype); Prov. San José, County Dota , District Jardin, viz. La Chonta, Finca Sta. Maria, 4 km on Hwy 2 from intersection at Empalme, N9°41.806, W83°55.763', 14.VIII.2014, JLM 2219 ( USAM); Same location, same date, JLM 2221 ( USAM) .

Figures

Figure 17. Gymnopus foliiphilus var. costaricensis. A Basidiomata and rhizomorphs B Pileus underside showing lamellar spacing C Pleurocystidia D Basidia E Pileipellis hyphae, showing encrustation and lobose side-branches F Basidiospores. Standard bars: A = 5 mm; B = not to scale; C-E = 20 µm; F = 5 µm. TFB 9750.

Figure 18. Gymnopus foliiphilus var. costaricensis. Pileipellis elements. A, B Firm-walled hyphae with slime sheath and crust material on exterior of the sheath C-J Diverticulate hyphae with individual lobate outgrowths K, L Extended lobes into ribbon-like proliferations. Standard bars = 10 µm. TFB 9750.

Figure 19. Gymnopus foliiphilus var. costaricensis. Hymenial elements. A-D Pleurocystidia E-H Basidia. Standard bars = 10 µm. TFB 9750.

Figure 20. Gymnopus foliiphilus var. costaricensis. Cheilocystidia. A Overview of lamellar edge B-E Individual cheilocystidia. Standard bars = 10 µm. JLM 2221 (USAM).

Figure 21. Gymnopus foliiphilus var. costaricensis. Caulocystidia. A Individuals from near stipe apex B Individuals from lower stipe. Standard bar = 20 µm.