Mycetinis copelandii (Peck) A. W. Wilson & Desjardin 2005. Mycologia 97: 677.

Petersen, Ronald H. & Hughes, Karen W., 2017, An investigation on Mycetinis (Euagarics, Basidiomycota), MycoKeys 24, pp. 1-138 : 17-20

4. Mycetinis copelandii (Peck) A. W. Wilson & Desjardin 2005. Mycologia 97: 677.

Marasmius copelandii Basionym. Peck 1904 Bull. Torrey Bot. Club 31: 182.

Holotype.

California, San Mateo Co., Woodside, N37°25'49", W122°15'12", 7.XII.1902, coll. EB Copeland, Copeland 14 (herb. Peck, NYS).

Diagnosis.

1) Basidiomata small but robust; 2) fruiting preference on dead Lithocarpus leaves; 3) pileipellis constructed of broadly clavate to obpyriform cells and complex free-form textura intricata hyphal termini; 4) cheilocystidia basically clavate but often with a few prominent apical lobate outgrowths; 5) basidiospores (9-)10.5-12(-15) × 3-4(4.5) µm, with heterogeneous contents; 6) pleurocystidia presumptive, cylindrical to narrowly fusiform; 7) stipe entirely vestured, furry at base; 8) caulocystidia of two width classes; 9) distribution in northern California.

Description.

Basidiomata (Fig. 20) small but robust. Pileus (4-)8-24 mm broad, convex when young, becoming shallowly convex, plane to shallowly everted in age, smooth, dry to moist, subglabrous, usually entirely fading in color in age; disc "Verona brown" 6E5, "bone brown" 7F8, "Sudan brown" 6E7. "Argus brown" 6E8, “auburn” 7E5, "Vandyke brown" 7E6, "burnt umber" 7E7, to "Kaiser brown" (6-7E5-8) when young, fading to near "buffy brown" 6D4-5, near "buckthorn brown" 5C5-7 or near “drab” 6C4 in age; margin at first incurved, entire, even, "buffy brown" 6D4-5, “Rood’s brown" 6-7D4-5, soon becoming decurved, shallowly translucent-striate, in age rugulose-striate, near "tilleul buff" 5B4 or "pale cinnamon pink" 5A2-3; trama 0.5-1 mm thick, near "sayal brown" 6C3. Lamellae adnate to adnexed, close to subdistant (13-16 reach the stipe), thickish, occasionally pseudocollariate, subventricose, shallow (1-1.5 mm width), rarely forked or intervenose, at first "pale cinnamon pink" 5A2, becoming near "tilleul buff" 6B3 in age, often spotted “Rood’s brown" 7D5-6 to "vinaceous russet"8D4, developing necropigment of "light ochraceous buff" 5A4; edges even and entire when young, concolorous with or slightly paler than the faces; lamellulae in 1-2 series. Stipe (15-)25-65(75) × 1-4 mm, terete when young, often becoming compressed in age, equal or tapered somewhat downward, non-insititious, occasionally somewhat rooting, tough, pliant, hollow to stuffed, vestured overall, pruinose to pubescent upward and there "pale cinnamon pink" 5A2 when young, becoming slightly darker in age, in midsection pubescent to velutinous, near “drab” 6C3, "wood brown" 7C4 or “Rood’s brown" 7D5-6, "walnut brown" 7D4-6, downward to base tomentose, “auburn” 7E5, "Vandyke brown" 7E6, "burnt umber" 7E7, "Kaiser brown" 7E5-8, “blackish-brown(1)” 7F5, "warm sepia" 7E6, "carob brown" 7E7, "bone brown"7F5-8 or "seal brown" 8F4-5. Rhizomorphs rare, obscure, -6 × 0.5-1.0 mm, black, strap-shaped, occasionally branched; short, narrow disarticulated stipes rare to abundant. Odor strongly of garlic but ephemeral; taste strongly alliaceous, persisting in herbarium specimens.

Habitat and phenology.

Gregarious to densely gregarious, clustered to subcespitose on or among senescent leaves of Quercus , Castanopsis and Lithocarpus in mixed, coastal forests; common; October-January.

Pileipellis (Fig. 21) a roughly hymeniform layer of two types of smooth cells: 1) broadly clavate to vesciculose, sphaeropedunculate, obpyriform or irregularly lecythiform cells 13-33(-90) × 6.6-14.4(18) µm, smooth to minutely roughened, occasionally with adventitious conical to lobate outgrowths, seldom lobed or bifid, firm- to thick-walled (wall - 1 µm thick), sometimes with ochraceous to brown walls up to 1.5 µm thick; and 2) free-form lobate termini (Fig. 22), stalked (stalk 7-<50 × 3.5-6.5 µm, inconspicuously clamped), -55 µm broad; contents heterogeneous. Pileus and lamellar tramae loosely interwoven; hyphae of two types: 1) 2.5-5.5 µm diam, firm-walled, conspicuously clamped; and 2) 4.5-17 µm diam, firm-walled, usually narrowing at septa, inconspicuously clamped; contents heterogeneous. Pleurocystidia (Fig. 23) presumptive (see below), 25-44 × 4-6 µm, cylindrical to narrowly fusiform, conspicuously clamped; contents more or less homogeneous. Basidia (Fig. 24) 27-39 × 6-10 µm, usually straight and rod-like, narrowly clavate, often subtly subcapitulate, 4-sterigmate, obscurely clamped. Basidiospores (Fig. 25A) (9-)10.5-12(-17) × 3-4(4.5) µm (Q = 2.63-3.83; Qm = 3.29; Lm = 11.75 µm), marasmioid (distally rounded, proximally tapered), sometimes slightly curved, smooth, thin-walled; con tents multiguttulate. Cheilocystidia (Fig. 26) 30-48(-60) × (7-)9-15 µm (at widest point), usually significantly larger than basidia, clavate, broadly clavate to ventricose-rostrate, stalked (stalk 7-20 × 4-5.5 µm, obscurely clamped), often with adventitious apical outgrowths, thin- to firm-walled, hyaline; contents homogeneous; outgrowths usually two, stout and digitate, occasionally more complex. Stipe medullary hyphae strictly parallel, tightly packed, (2-)4-8 µm diam, firm- to thick-walled (wall -0.5 µm thick), free (without slime matrix; not adherent in sheets), obscurely clamped, hyaline. Stipe cortical hyphae 4-8 µm diam, thick-walled [wall -2 µm thick, weakly pigmented (PhC)], producing caulocystidia as side branches or hyphal termini. No stipe tissue dextrinoid. Caulocystidia from upper stipe (Fig. 25B) 20-250 × 4-10 µm, more or less equal, rounded at apex, thick-walled (wall -1.5 µm thick, weakly pigmented near origin), often prominently clamped, occasionally branched, never straight, irregularly curved or kinked, in fascicles. Caulocystidia from stipe base (Fig. 27) 20-900 µm long, in two width ranges with intermediates: 1) 5-13 µm broad, predominant, thick-walled [wall - 2 µm thick, weakly pigmented (PhC)]; and 2) 12-21 µm broad, widely scattered in fascicles of 2-4 individuals, thick-walled (wall -8 µm thick often occluding cell contents), distinctly pigmented.

Commentary.

The free-form cells of the pileipellis are reminiscent of those of members of Gymnopus (Micromphale) sect. Perforantia and ( Marasmius ) sect. Androsacei but are considerably more complex. The size of the lobes are like the broader lobes of some pileipellis lobes in the same groups.

Pleurocystidia are either absent or undifferentiated. Subjective judgement on their presence is based on: 1) ubiquitous presence in other taxa of Mycetinis and related groups; 2) narrow width as compared with immature basidia of more or less equal length; and 3) no evidence of distal heterogeneous contents, as opposed to developing basidia of more or less equal length.

When comparing M. olidus with M. copelandii , Desjardin (1987a) summarized macromorphological characters considered taxonomically important in Marasmius (e.g. macroscopic features, substrate, stipe attachment, and microchemical reactions) and concluded that the two were micromorphologically indistinguishable, but M. olidus , commonly collected in eastern North America, not only produced consistently smaller basidiomata on non-sclerophyllous leaves, but is allopatric with M. copelandii . Consequently, M. olidus is treated here at species rank.

Desjardin (1987b) considered Marasmius copelandii to be the most commonly collected alliaceous marasmioid fungus in California, fruiting in mixed coniferous/tan bark oak forests and oak woodlands along the California coast from San Diego County to Mendocino County, and in similar habitats in the foothills of the Sierra Nevada, Siskiyou and Trinity mountain ranges.

A single collection of putative Ma. copelandii (TENN55408-TFB 8084, based on spore dimensions) produced ITS sequences essentially congruent with those of Ma. salalis (1bp difference/722bp). This anachronism provokes the question of morphological discrepancies (in this case largely spore dimensions) versus molecular similarity. One solution is that Ma. salalis / Ma. copelandii produces long- and short-spored forms. A more accurate assessment will be possible when additional sequences become available and/or when multigene trees are produced.

Specimens examined.

California, Santa Cruz Co., Martin Rd., Fire Station, N37°03'03.6", W122°08'19.2", 13.XII.1983, coll. AS Methven (as Marasmius siccus ), annot. D.E. Desjardin (as Marasmius copelandii ) ASM 2676 (TENN57185); San Mateo Co., San McDonald County Pk., N37°18'31.7", W122°15'31.9", 12.XII.1983, coll AS Methven, annot. D.E. Desjardin (as Marasmius copelandii ), TENN-F- 57189;