Mycetinis virgultorum ( Malencon & Bertault) R.H. Petersen, stat. nov.

Petersen, Ronald H. & Hughes, Karen W., 2017, An investigation on Mycetinis (Euagarics, Basidiomycota), MycoKeys 24, pp. 1-138 : 60-61

13. Mycetinis virgultorum ( Malencon & Bertault) R.H. Petersen, stat. nov.

Marasmius scorodonius var. virgultorum Basionym. Malençon & Bertault. 1975. Flores des champignons superieurs du Maroc II: 378(-382). ≡ Mycetinis scorodonius var. virgultorum ( Malençon & Bertault) Antonín & Noordel. 2008. Czech Mycol. 60: 26.

Holotype.

Morocco, herb. Malençon, no. 5663, Institute Montpelier (MPU) [material unavailable].

Diagnosis.

1) Basidiomata diminutive (pileus 3.5-8 mm broad; stipe 7-18 × 0.4-0.5 mm), marasmielloid; 2) distribution trans-Mediterranean; 3) fruiting on canes of Rubus and other deciduous detritus; 4) stipe vestured overall or at least upward; 5) stipe pale upward, downward brown-red; 6) spores 7-8 × 3.6-4.3 µm.

The following description is a combination and rearrangement of descriptions by Malençon and Bertault (1975), Eyssartier and Moreau (2001), and Antonín and Noordeloos (2010).

Description.

Basidiomata (Fig. 85A) diminutive, marasmielloid. Pileus 3.5-8 mm broad, hemispherical when young and then subumbonate, becoming convex then applanate, in age usually applanate to everted, not hygrophanous, drying uniformly, thin and supple, dry, sometimes subrugulose, obscurely bruised over disc, pruinose and finely powdery or minutely saccharine-granular; disc reddish alutaceous, between ferrugineous and fulvous (Saccardo, Chromotaxia), dark reddish ( Eyssartier and Moreau 2001); margin involute when young, then downturned, entire, sometimes visibly striate in age, paler than disc to off-white, perhaps with weak pinkish tint ( “beige-carné” teste Eyssartier and Moreau 2001). Lamellae adnexed to nearly free (broadly adnate to emarginated (teste Antonín 1995), -1.5 mm broad, moderately close to distant, total lamellae 12-15 (19-22 test Antonín (1995); 20-24 teste Eyssartier and Moreau 2001), through lamellae 4-6 (two teste Antonín 1995), acute toward pileus margin, enlarged and sinuate near attachment, white to cream-colored on face, rosy cream on sinus, in rugulose ridges, finally interveined or reticulate in age; lamellar edge concolorous, pubescent (teste Antonín 1995); lamellulae in one rank (teste Eyssartier and Moreau 2001). Spores white. Stipe (4-)7-18(-25) × 0.3-0.5(-1) mm, slender, terete, equal through its major part although dilated under the lamellae and sometimes subbulbous at base, erect or ascendant, rigid, insititious (teste Antonín 1995) hollow when adult, a little pruinose at apex, downward smooth or hairy (entirely furfuraceous-squamulose, strigose at base, teste Antonín 1995) ("avec seulement quelque courts trichoïdes bruns àla base" teste Eyssartier and Moreau 2001), cream colored at apex, amber and darker to brown-red downward ("rouge-purpurin sombre" teste Eyssartier and Moreau 2001). Flesh thin, white or weakly tinted under the union to stipe or apex of stipe, rosy at its base. Odor of garlic, perceived in nature even before the basidiomata; taste similar (teste Antonín 1995).

Habitat and phenology.

Fruiting on canes of Rubus discolor , decaying deciduous leaves and twigs, including Quercus coccifera , Vibernum , Erica ; distribution (see Antonín 1995; Antonín and Noordeloos 2010; Eyssartier and Moreau 2001) trans-Mediterranean Sea, as far north as France (Bon 1994); March, June, October, November, December.

Pileipellis (Fig. 85B) composed of a coarse hymeniform layer of hyphal termini of two types: 1) about 20-30(-40) × (7-)10-15(-40) µm, clavate, broadly clavate to obpyriform,, firm- to thick-walled (wall <1 µm thick), sometimes pigmented brownish (teste Antonín 1995); and 2) firm-walled, deformed or arbuscularly branched with irregular digitate protuberances. Pileus flesh interwoven, lacunose, composed of filamentous hyphae 3.5-8 µm diam, branched, clamped, secondarily septate, often encrusted with plaques and/or zebroid deposits. Pleurocystidia probably present, fusiform (see illustration of basidioles by Eyssartier and Moreau 2001). Basidioles cylindrical to narrowly clavate; basidia 23-31 × 5-7 µm, cylindro-clvate, 4-sterigmate, clamped at base; sterigmata more than 3 µm long. Basidiospores (Fig. 85D) 7-8 × 3.6-4.3 µm, ellipsoid to subnavicular to a base with small, oblique apiculus, hyaline, thin-walled, inamyloid. Lamellar edge sterile; cheilocystidia (Fig. 85C) 15-30 × 6.2-9.2 µm (teste Antonín 1995), hyaline, clavate to subglobose, surmounted by coarse, mostly digitate or coralloid diverticula. Stipe medullary hyphae 10-13 µm diam, strictly parallel, firm- to thick-walled (wall -2.5 µm thick), resembling large fibers, which cover the bottom of the stipe. Stipe cortical hyphae 3-4(-6.5) µm diam, thick-walled (wall -1.5 µm thick, pigmented). Caulocystidia (teste Antonín 1995) in scattered bundles of (sub)erect, cylindrical hyphae present on stipe surface.

Commentary.

The description above is adopted from those cited herein. Although the abbreviated translation of Malençon's and Bertault (1975) description presents an outline of characters, descriptions of other characters are missing: 1) stipe seems to be smooth, without caulocystidia, although caulocystidia are reported by others; 2) stipe insertion is illustrated as insititious but not described as such; 3) pleurocystidia are reported as absent, but “basidioles” are reported as clavate or fusoid, and the fusoid structures are probably pleurocystidia. Antonín (1995), based on a specimen from Italy, and Eyssartier and Moreau (2001) offered more complete descriptions, but still without recognition of pleurocystidia.

Antonín’s (1995) report of spore dimensions: (5.8-)6.3-7.7 × 3.1-3.8 µm [E = 1.8-2.0(-2.3), Q = 2.0]. Spore measurements by Eyssartier and Moreau (2001): 6.5-7.5 × 3-4(4.5) µm.

Malençon and Bertault (1975) had opportunity to see M. scorodonius , which also produced a strong garlic odor, and concluded that their organism was a dwarf state. Simultaneously, however, their basidiomata resembled more closely those of M. (Ma.) ramealis , differing in pileipellis characters.

A parallel situation of basidiomatal size concerns My. copelandii var. olidus , in which basidiomatal size, fruiting substrate and distribution of the variety all differ from its parent species. My. olidus is here proposed at species rank. Likewise, in light of basidiome size throughout Mycetinis , which seems to sort into two categories, it is difficult to treat My. virgultorum as a variety under My. scorodonius , so it is here proposed at species rank.

Desjardin and Horak (1997) mentioned similarities between M. curraniae and M. scorodonius var. virgultorum . The two would seem to exhibit similar morphological characteristics, but fruiting substrate and a circum-Mediterranean distribution would seem exclusive to the Antipodal fungus. Perhaps comparison should be made also with My. cinnamomeus from South Australia. When molecular data on My. virgultorum become available, this situation may be elucidated.