Diplocarpon mespili (Sorauer) B. Sutton, The Coelomycetes (Kew): 150 (1980)
= Entomosporium mespili (DC.) Sacc., Michelia 2(no. 6): 115 (1880)
Facesoffungi number: FoF 07318
Parasitic on the host plant. Sexual morph: see Sutton (1980). Asexual morph: Conidiomata 100–750 µm diam., 30–100 µm high, yellowish brown to dark brown, stromatic, acervular, amphigenous, but mostly epiphyllous, solitary to gregarious or confluent, subcuticular in origin, oval to rounded or occasionally sunken in the middle zone or irregular in outline, rugose, dehiscing by an irregular break in the host cuticle. Conidiomatal wall 10–70 µm wide, mixed with host plant tissue, of a loose textura angularis, with thick-walled, pale brown to brown cells and encrusted in the lower layers, becoming hyaline towards the upper layers. Conidiophores formed from the innermost layer of wall cells, hyaline, branched at the base, septate. Macroconidiogenous cells 7–12 × (3–)4–5 µm, hyaline, enteroblastic, phialidic, cylindrical, determinate, smooth-walled. Macroconidia hyaline, cruciform, mostly 4-celled, occasionally 3–6-celled; basal cell 6–12 × 4–7 ( = 8.6 × 5.5 µm; n = 30), short cylindrical to globose, with truncate or obtuse base, bearing minute marginal frill; apical cell 7–15(–18) × (6.5–)7–9 ( = 11 × 8; n = 30), globose with obtuse apex; lateral cells 3.5–7.5 × 3–5(–5.5) (= 5.3 × 4 µm; n = 30), mostly 2, sometimes 1–3, globose to ellipsoidal, smaller than the apical and basal cells, formed from the upper part of the basal cell; apical and each lateral cell bearing a single, tubular, unbranched, attenuated, flexuous appendage, 2–4 ( = 53) µm long. Microconidial synanamorph occasionally developing in the same or separate conidiomata. Microconidiogenous cells 6–10 × 2–3 hyaline, annelidic, cylindrical to lageniform, broader at base, discrete or integrated, indetermined, smooth-walled. Microconidia (3–)4–6 × 1–1.5(–2) ( = 3.5 × 1.3 µm; n = 30), hyaline, narrowly ellipsoidal, truncated at base, obtuse at apex, unicellular, smooth-walled.
Material examined: Canada, Ontario, Byron nr. London, on leaf of Amelanchier canadensis (Rosaceae), 16 August 1910, J. Dearness (FH 01142401, Kabát & Bubák - Fungi Imperfecti Ex s. #826).
Diplocarpon mespili (asexual morph, FH 01142401). a, b Herbarium specimen. c, d Appearance of yellowish brown to brown conidiomata (arrows) on the host. e–g Vertical section of conidiomata. h–l Conidiophores, conidiogenous cells and developing conidia. m–p, r–u Macroconidia. q Microconidia. Conidia. Scale bars c–d = 200 µm, e–g = 100 µm, h–p, r–u = 10 µm, q = 5 µm.
Li WJ, McKenZie EHC, Liu JK, Bhat DJ, Dai DQ, Caporesi E, Tian Q, Maharachcikumbura SSN, Luo ZL, Shang QJ, Zhang JF, Tangthirasunun N, Karunarathna SC, Xu JC, Hyde KD (2020) Taxonomy and phylogeny of hyaline-spored coelomycetes. Fungal Diversity 100: pages279–801.