Mycetinis cinnamomeus (Cleland) R.H. Petersen & Desjardin, comb. nov.

Petersen, Ronald H. & Hughes, Karen W., 2017, An investigation on Mycetinis (Euagarics, Basidiomycota), MycoKeys 24, pp. 1-138 : 15-17

3. Mycetinis cinnamomeus (Cleland) R.H. Petersen & Desjardin, comb. nov.

Marasmius cinnamomeus Basionym. [as “cinnamoneus”] Cleland. 1934. Toadstools & Mushrooms and other larger fungi of South Australia (addenda) 1: 132. [non Cleland. 1934. Trans. Roy. Soc. S. Australia 58: 213].

Type

[lectotype, design. ( Grgurinovic 1997)]: Australia, South Australia, Belair Nat. Park, S35°00'44.79", E138°38'54.54 ", 7.VII.1934, coll. J.B. Cleland, Cleland no 10002 (AD 10986).

Diagnosis.

1) Basidiomata diminutive (pileus 4-12 mm broad; stipe 6-12(-25) × 0.6-1 mm); 2) pileipellis hymeniform, of firm- to thick-walled inflated hyphal termini; 3) basidiospores broadly ellipsoid to subamygdaliform; 4) caulocystidia absent; 5) reported lack of odor; 6) habitat on bark of living eucalypts; 7) fruiting in late autumn to winter; South Australia.

The following description is a combination of the protolog, Grgurinovic’s (1997) treatment and Desjardin’s notes (pers. comm.) on three Cleland specimens.

Description.

Basidiomata diminutive. Pileus -12 mm broad, at first convex with inturned margin, then nearly plane, "light pinkish cinnamon" 7A2, "pinkish buff" 6A3, "light vinaceous cinnamon" 7A3 or "light ochraceous salmon" 6A4, darker over the disc; surface dull and slightly villose or minutely frosted, subrugose, sometimes shallowly substriate at margin. Lamellae adnate, then seceding, moderately close to somewhat distant, presence or absence of pseudocollarium unreported, slightly ventricose, cream-colored or white; edge sometimes appearing delicately serrulate. Stipe -12(-25) × 0.6-1mm, subinsititious, slender, slightly velutinous or smooth, near "Hessian brown" 9E7 or "Vandyke brown" 7E6, paler above, downward darker, sometimes nearly black below. Odor reported as negligible; taste not recorded.

Habitat and phenology.

Gregarious on thick bark at the bases of living eucalypts; South Australia; May-July.

Pileipellis (Fig. 19A) more or less a hymeniform layer of inflated hyphal termini not involved in a slime matrix; cells clavate, obpyriform, sphaeropedunculate, molar-shaped to coarsely lobed, firm- to thick-walled (wall 0.5-2.5 µm thick), occasionally with irregular short apical diverticula, hyaline to golden brown; diverticula 15.2-29.6 × 7.8-13.6 µm. Subpellis hyphae cylindrical, not encrusted, conspicuously clamped. Pleurocystidia not reported but probably narrowly fusiform as in other taxa of the genus. Basidioles clavate; basidia 24.0-32.0 × 6.2-10.0 µm, clavate, sometimes versiform in midsection, 2-4-sterigmate; sterigmata -6.0 µm long. Basidiospores (Fig. 19B) 7.2-10.2 (-12) × 3.4-5.1(-6.2) µm [Qm = 2.0; Lm = 8.4 µm], ellipsoid, subovate to subamygdaliform, smooth, thin-walled, inamyloid. Lamellar edge fertile; cheilocystidia (Fig. 19) scattered, (11.2-)18.4-33.6 × 5.6-16 µm, broadly clavate, hyaline, firm-walled, clamped; main body 13-20 × 7-9 µm, hyaline, diverticulate; diverticula 3-8 × 1.5-3 µm. Stipe cortical hyphae 3-6.5 µm diam, parallel, cylindrical, thick-walled, orange brown, with granular to annular encrustation. Caulocystidia absent.

Commentary.

Desjardin and Horak (1997) drew attention to similarities between M. curraniae Stevenson from New Zealand and M. cinnamomeus from South Australia. Since then, M. curraniae has been recombined into Mycetinis ( Cooper and Leonard 2012) and molecular data have shown its placement with other taxa of Mycetinis . Unfortunately, molecular data for M. cinnamomeus have not yet been produced, but Cleland’s report of "odour none" notwithstanding, all other characters point to its inclusion with other taxa of Mycetinis , especially those with diminutive basidiomata (i.e. My. olidus , M. yunnanensis ). The proposed nomenclatural new combination is intended to bring this additional taxon into Mycetinis .

Grgurinovic (1997) translated Clelend’s (1934) Latin description into English, adding observations on microstructures.

As is common for some other taxa of Mycetinis , M. cinnamomeus was considered by Grgurinovic (1997) as belonging in Marasmius sect. Epiphylli , and Desjardin and Horak (1997) indicated section Chordales (by implication of similarity to M. curraniae ). Other than literature cited here, little is known about Cleland’s taxon. It seems to have eluded collection since Cleland’s finds. The diminutive basidiomata seem similar to those of M. virgultorum , M. olidus , M. curraniae and M. yunnanensis .

Cleland (1934) listed four locations as distribution of M. cinnamomeus : Belair National Park (S35°00'44.79", E138°38'54.54"), Willunga Hill (S35°18'44", E138°34'35"), Mt. Lofty (S34°58'25.65", E138°42'32.25") and Inman Valley (S35°28'00.30", E138°27'19.06"). Both Grgurinovic (1997) and Desjardin (unpubl.) examined AD 10986, while Desjardin examined two additional specimens.

Spore dimensions by Cleland (1934) and Grgurinovic (1997) are somewhat smaller than those by Desjardin (in litt. and included above).

Specimens examined (by DED): Australia, South Australia, Willunga Hill, 31.V.?, coll. J.B. Cleland, Cleland no. 10037 (AD 31401); South Australia, Belair Nat. Park, 7.VII.1934, coll. J.B. Cleland, Cleland no 10002 (AD 10986, lectotype); South Australia, National Park, 28.V.1927, coll. J.B. Cleland, Cleland no. 392 (AD 31402).