Diaporthe arezzoensis W.J. Li, Camporesi & K.D. Hyde, sp. nov.
Index Fungorum number: IF557207
Etymology: Refers to the name of the province in Italy where the fungus was collected
Saprobic on dead stems of Cytisus sp. Sexual morph: undetermined. Asexual morph: Conidiomata 350–400 µm diam., 300–450 µm high, brown to dark brown, pycnidial on the upper surface of stem, solitary, initially closed, later opening to become disciform to cupulate, immersed to erumpent, globose to subglobose, unilocular, motilocular or convoluted, ostiolate. Ostiole circular, centrally or laterally located. Conidiomatal wall 20–240 µm wide, composed of thick-walled, dark brown cells of textura intricata in the outer wall layer, becoming pale brown cells of textura angularis towards inner layers. Conidiophores reduced to conidiogenous cells. Conidiogenous cells 16–30 × 2–6 µm, hyaline, enteroblastic, phialidic, subcylindrical, tapered to the apices, determinate, unbranched, smooth-walled, with periclinal thickenings at collarette zone. Conidia hyaline, of two types, a) α-conidia 13–20 × 5–9 µm (= 16 × 7 µm; n= 50), fusiform to oblong, straight, aseptate, thick- and smooth-walled eguttulate; b) β-conidia, 22–30 × 1–3 µm (= 26 × 2 µm; n= 50), filiform, acute at both ends, straight or more often hamate, aseptate, eguttulate.
Material examined: Italy, Province of Arezzo, near Croce di Pratomagno, on dead land branches of Cytisus sp. (Faboideae), 1 October 2012, Erio Camporesi, IT752 (MFLU 19-2880, holotype), ex-type living culture MFLUCC 15-0127 = ICMP 21837 = KUMCC 15-0581, (KUN, HKAS93664, isotype), ibid., Province of Arezzo, Bagno di Cetica, 7 October 2012, Erio Camporesi, IT792 (MFLU 19-2883), (KUN, HKAS 93606).
Notes: The description of our collections fits well within the generic concept of asexual morphs of Diaporthe. These collections have much larger, wider and thick-walled α-conidia than other taxa. In the phylogeny, our strains formed a separated branch.
Diaporthe arezzoensis (MFLU 19-2880, holotype) a Herbarium specimen. b, c Appearance of brown to dark brown conidiomata on the host. d, e Vertical sections of conidiomata. f Ostiole. g Section of peridium. h–l Conidiogenous cells and developing conidia. m Germinating conidium. n–o Conidia. Scale bars b = 1000 µm, c = 300 µm, d–e = 200 µm, f–g = 50 µm, h–o= 10 µm.