Micromphale bulliformis 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 : 9-15

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Micromphale bulliformis R.H. Petersen

sp. nov.

1. Micromphale bulliformis R.H. Petersen sp. nov.


United States, Washington, Jefferson Co., Olympic National Park, Tunnel Creek, N47°46'44.19", W123°03'25.83", VIII.1975, coll F. VanDeBogart (as Ma. androsaceus ), FVDB 3621 ( WTU-F-51955).


Bulliformis = bubble-like, referring to the appearance of cheilocystidia at lamellar edge.


1) Morpho-species (no DNA sequences available); 2) stipe vesture a loose thatch of tortuous, often-branched, thick-walled caulocystidia; 2) cheilocystidia bulbous, smooth, with homogenous contents; 3) basidial sterigmata unusually long and slender; 4) pleurocystidia sharply fusiform, with poorly-defined content partitioning; 5) pileipellis involved in slime matrix.

The description which follows is compiled from examination of dried material. Colors when fresh may vary considerably from those below.


Basidiomata (Fig. 1A, B View Figure 1 ) diminutive, robust. Pileus 3-14 mm broad, convex, usually somewhat flattened over disc and occasionally with suggestion of small umbo, matt, sulcate near margin but not striate; disc near "Verona brown" 6E5; limb and margin near "sayal brown" 6C5 or "cinnamon buff" 6B4; context thin, fragile. Lamellae adnate to adnexed, not pseudocollariate, thin, becoming ventricose by maturity (-2.5 mm broad) and strongly crisped (dry), subdistant to distant with no anastomoses or interveining, total lamellae = 25-38, through lamellae = 13-18, (fresh) near "ochraceous buff" 5A5 to “chamois” 4B4, (dry) between "ecru drab" 16B2, "olive ochre" 2B8 and "deep olive buff" 3C3, suffusing to brown ("sayal brown" 6C5) from edge in age; lamellulae in 1-2 tiers, often rudimentary. Stipe 16-35 × 0.5-0.8(-1) mm, probably terete when fresh, equal, occasionally abruptly changing directions as though adventitious from being broken, subinsititious, pilose-vestured from apex to base, lightly so upward and there with vesture pallid, downward delicately barbed and more so to felty at base, producing a matted-furry appearance, irregularly elongate-maculate with blond vesture and fuscous pileus surface (dried), but somewhat more prominently vestured upward, upward "clay color" 5C6 or “cinnamon” 6B5, downward "snuff brown" 5E8 to "Verona brown" 6E5 at base, at junction with lamellae dark brown and leaving delicate brown ring in pileus trama. Rhizomorphs undetected. Taste and odor not recorded.

Habitat and phenology.

Temperate rainforest; substrate uncertain, certainly dead conifer needles, perhaps Tsuga or Abies ; mid-summer.

Pileipellis composed of three elements, all involved with a heterogeneous slime matrix (Fig. 3 View Figure 3 ): 1) pileal hairs (Fig. 2 View Figure 2 ) -120 × 3.5-7 µm, cylindrical with slightly enlarged apex, thin- to firm-walled, occasionally internally clamped; 2) repent hyphae 3-9 µm diam, thin- to firm-walled (wall gelatinizing to 1.5 µm thick; Fig. 3C, D View Figure 3 ), weakly encrusted (crusting material flake-like, often riding on a thin slime sheath, detersile in slime matrix), conspicuously clamped; and 3) significant hyphal segments with numerous secondary septa (Fig. 3A, B View Figure 3 ). Pileus trama loosely interwoven; hyphae 3-9 µm diam, gelatinizing and with thin slime sheath, conspicuously clamped. Lamellar trama identical. Pleurocystidia (Fig. 4 View Figure 4 ) 22-34 x 7-9 µm, fusiform, unusually sharply pointed, often somewhat swollen in mi-shaft, conspicuously clamped; contents partitioned, but ill-defined. Basidia (Figs 5 View Figure 5 , 7A View Figure 7 ) 24-30 × 7-9 µm, broadly clavate, conspicuously clamped, 4-sterigmate; contents heterogeneous with inclusions appearing oily (PhC); sterigmata -8 × 1 µm, awl-shaped. Basidiospores (Fig. 1C, D View Figure 1 ) (6.5-)7-7.5(-8) × 3.5-4(-4.5) µm (Q = 1.73-2.14; Qm = 1.88; Lm = 7.20 µm), ellipsoid, subgymnopoid (slightly tapered proximally), smooth, thin-walled, inamyloid. Cheilocystidia (Figs 6 View Figure 6 , 7B-G View Figure 7 ) locally common, 15-26 × 9-15 µm, broadly clavate to subglobose, thin- to firm-walled, obscurely clamped, occasionally with one or two vermiform apical outgrowths (usually without); contents homogeneous, appearing empty. Stipe apex medullary hyphae strictly parallel, 5-9 µm diam, thin- to firm-walled but soon gelatinizing (in KOH) so walls become almost indistinguishable, often encrusted with crust material riding on outer surface of slime sheath, obscurely clamped. Stipe apex cortical hyphae 3-6 µm diam, long-celled, conspicuously clamped, thick-walled (wall often obscuring cell lumen), producing a layer of inflated, thick-walled cells and caulocystidia as side branches; caulocystidia from upper stipe (Fig. 8 View Figure 8 ) 10-75 × 4-8 µm, irregularly cylindrical, usually with basal clamp, thick-walled (wall -2 µm thick, with cell lumen irregularly defined), subhyaline. Mid-stipe medullary hyphae strictly parallel, 3.5-12 µm diam, thick-walled (wall -2 µm thick), obscurely clamped, involved in a slime matrix but not with gelatinizing walls; mid-stipe cortical hyphae as above, producing a thatch of tortuous, thick-walled side branches resembling stipe-apex caulocystidia, from which extended caulocystidia (Fig. 9F View Figure 9 ) arise; caulocystidia - 125 × 4-8 µm diam, thick-walled, cylindrical, refringent (PhC), usually oriented parallel to stipe surface.


Proposal of another species of Gymnopus (Micromphale) section Perforantia would seem problematic, especially from a region relatively rich in such taxa, but presence and uniqueness of diagnostic characters make such a proposal relatively safe. The diagnosis (above) lists characters which separate G. (Mi.) bulliformis from other members of sect. Perforantia with diminutive basidiomata.

The temperate rain-forests of the North American Pacific coastal region of United States and Canada apparently support several taxa of the androsaceoid/perforantioid complex. Loan of selected specimens (using Mycoportal as filter) under only Ma. androsaceus and Mi. perforans revealed enough new taxa to make intensive collecting worthwhile for such organisms. This might not be surprising, considering the variety of conifer trees, on the dead needles of which such diminutive basidiomata are to be found.

Separation of taxa in Micromphale sect. Perforantia is difficult. Micromphale perforans occurs in Europe and Scandinavia through northern North America, presumably continent-wide. It may be present in northeastern and western Siberia as well, but this is beyond the scope of this paper. From northern California comes M. sequoiae which closely resembles G. bulliformis but is reported as limited to dead foliage of Sequoia sempervirens . Both taxa are reported as lacking (or rare) cheilocystidia, neither taxon exhibits much differentiation in the pileipellis, and caulocystidia are quite similar, although those of M. perforans are reported as exhibiting some denser, more refringent (PhC) pigment at caulocystidial tips. Ordinarily, M. perforans exhibits a black, vestured stipe when mature, but Antonín and Noordeloos (2010) include dark brown shades as well, and M. sequoiae seems also to form a dark brown stipe. Desjardin (1985) used the following characters to separate M. sequoiae from M. perforans : 1) light brown to flesh-colored pileus versus pale pileus respectively; 2) mild odor versus strong, fetid odor respectively; 3) greyish orange to brown pubescent stipe versus black velutinous stipe respectively; 4) caulocystidia without concentrated apical pigment versus caulocystidia with concentrated apical pigment respectively; 5) habitat on Sequoia debris versus conifer needles, usually Picea and/or Abies respectively.

Attempts were made to obtain ITS sequences from both collections of G. bulliformis , both unsuccessful. WTU-9305 yielded sufficient sequence to identify it as a member of the clade /perforantia and blasted weakly to G. perforans in GenBank. Whether G. bulliformis deserves phylogenetic distinction remains questionable until clean sequences can be obtained from “fresh” material.

Specimens examined.

Washington, Jefferson Co., Olympic National Park , Tunnel Creek , N47°46'44.19", W123°03'25.83", VIII.1975, coll F. VanDeBogart (as Marasmius androsaceus ), FVDB 3621 ( WTU-F-51955; holotype); Snowhomish Co., Barlow Pass, Barlow Pass study area, N48.02667, W121.44278 (WGS 84), 8.VII.1992, coll S. Trudell (as Micromphale perforans ), s.n. ( WTU-F-9305) GoogleMaps .