Metacampanella dendrophora
Metacampanella dendrophora (Singer) R.H. Petersen 2024, in Petersen & Hughes, Mycology, 16 (2024).
Synonymy:Pterospora dendrophora (Singer) E. Horak,Tetrapyrgos dendrophora (Singer) E. Horak, Metacampanella dendrophora f. washingtonensis R.H. Petersen
Basionym: Campanella dendrophora Singer, Mycologia 47 (5), 763 (1955)
Diagnosis: 1) Basidiomata (Figure 1) 1–5(−8) mm broad, broadly reniform to orbicular, distinctly laterally stipitate, conchate to Favolaschia-shaped, shallowly convex, cupulate to hemispherical, poorly dried basidiomata dark purplish-brown and cartilaginous; trama largely gelatinised, with gel appearing as pillow-like units not merging together (as though produced by individual hyphal cells); 2) pileus undulate to strongly pulvinate, puckered to subtly alveolate, matt, usually off-white to “tilleul buff” 7B2, with suffused patches of “pale olive buff” 3B2, slowly discolouring to “slate olive” 27E4, to “deep slate olive” 28E3, “tea green” 29C3, “Vetiver green” 29C4, “Andover green” 29D4 to 25E3-4, “dark ivy green” 29F4-5, or entirely without white; pileus necropigment “light ochraceous buff” 5A4, “cinnamon buff” 6B4; 3) hymenophore with 2–4 radial lamellar folds, with few (TFB 7357) to (usually) many meandering secondary rounded veins (not knife-edged) to appear merulioid or alveolate, <0.5 mm broad, when fresh white to “pale olive buff” 3B2; necropigment somewhat more orange than pileus to “light ochraceous buff” 5A4, “ochraceous buff” 5A5, “ochraceous tawny” 6C6; lamellar tramal hyphae similar to pileus trama, with gelatinised tissues appearing as scattered pockets; 4) stipe lateral, 0.5–1 × <0.5–0.5 mm, occasionally lacking, straight (when para- or negatively geotropic) to very strongly curved when geotropic, often slightly enlarged at base, vestured, white, inserted in substrate by a small basal pad concolorous with pileus; 5) odour and taste negligible; 6) basidiospores (5.5–)8–10 × (4.5–)6.0–7.0(−8) μm (E = 1.13–1.90; Em = 1.34; Lm = 8.25 μm), broadly ellipsoid to bulged abaxially to appear rounded-triangular to rounded-cuboid (derivative metrics of little value, depending on the view of individual spores), thin-walled, hyaline, smooth, inamyloid; hilar appendix narrow; contents minutely heterogeneous; 7) pleurocystidia 30–35 × 8–10 μm, weakly fusiform, inconspicuously clamped; contents subtly heterogeneous; 8) basidioles broadly clavate, inconspicuously clamped; contents increasingly heterogeneous with age; basidia 30–38 (−42) × 10–14 μm, clavate, often suburniform or with slightly enlarged distal portion, 4-sterigmate (sterigmata stout, strong, slightly curved), inconspicuously clamped; contents heterogeneous; 9) cheilocystidia lacking or scattered in small clusters, of two types: a) tetrapyrgoid (i.e. axial, often septate with median portion beset with numerous minute, branched ornamentation and usually with enlarged apical portion), 30–50 × 6–12 μm, hardly protruding beyond basidia/basidioles; b) metuloids rare to common (apparently not in all basidiomata), apparently cheilocystidial in distribution, widely scattered, (28–)30–45 × 10–15 μm, fusiform with rounded apex, to ampulliform, thick-walled (wall <1.2 μm thick, smooth, hyaline), easily disarticulated from basal septum, probably clamped, often (but not more than 50%) with apical crystalline deposit; apex difficult to observe; 10) pileipellis a tightly interwoven tissue of free (not gelatinized) ramified hyphae; superficial pileipellis composed as follows: a) thatch of arboreal hyphal termini; major axis 5–14 × 2.5–4.5 μm, often beset with numerous lateral outgrowths, from relatively simple to branching into 2–5 secondary branches, rebranching into crowded peg-like to awl-shaped termini 2–5(−15) × 1–1.5(−3) μm,; this is not strictly a Rameales-structure; b) thin-walled repent hyphae (2.5–4.5 μm diam.) beset with densely scattered small side branches (especially on the outer surface) resembling a Ramealis-structure; c) inner pileipellis a repent layer of encrusted hypha 3–5.5 μm broad, with encrustation usually of annular thickenings with deeper hyphae becoming gelatinized with walls disappearing; clamp connections ubiquitous; 11) fruiting chiefly on Chusquea (TFB 7357= TENN-F-054439), but also occasionally on dead dicot bark (TFB 8328 = TENN-F-055002), on dead ?Berberis (TFB 7340 = TENN-F-054442); fruiting on both Chusquea and on Nothofagus twigs (TFB 7335 = TENN-F-054395); presently known from Argentine Andes and Isla de Chiloé; April, May. Stipe medullary hyphae free (not involved in slime or gelatinous matrix), more or less parallel, of two types: a) 2–5.5 μm diam., firm- to thick-walled (wall <0.5 μm thick); and b) 4–11 μm diam., firm-to thick-walled (wall −1 μm thick), appearing somewhat glassy in PhC. Stipe cortical hyphae variable, 3–8(−24) μm diam., thick-walled (wall −2.5 μm thick, not uniform), producing copious side branches. Stipitipellis structures of two types: a) weakly “asterostromelloid” (Singer 1975; diverticulate with diverticula awl-shaped), with hyphae rather uniform, 2.5–4 μm diam., thick-walled (wall <0.7 μm thick, hyaline); diverticula 3–8 × 2–3.5 μm; and b) tetrapyrgoid, axial with inflated apical lobe; axis 8–27(−35) × 2.5–5 μm, with copious short diverticula, often curved towards distal terminus but usually rebranched into clusters of minute diverticulate outgrowths; outgrowths 0.7–3.5 × 0.5–2 μm; inflated terminal lobe broadly ellipsoid to elongate-obovate, 4–9(−12) × 4–7 μm, thick-walled (wall <1.5 μm thick, hyaline, somewhat refringent).
Index Fungorum Number: IF901404
Figure 1. Metacampanella dendrophora. Basidiomata, habit. (a) TFB 7335 (TENN-F-054395). (b) TFB 7340 (TENN-F-054442). Standard bars = 10 mm. (Photo: Petersen & Hughes 2024)