Graphiopsis

Graphiopsis Trail, Scottish Naturalist 10: 75 (1889).

≡ Dichocladosporium K. Schub., U. Braun & Crous, in Schubert et al., Stud. Mycol. 58: 96 (2007) (Braun et al. 2008).

Index Fungorum number: IF 8396; Facesoffungi number: FoF 06631, 1 morphological species (Species Fungorum 2022), 1 species with molecular data.

Associated with leaf spot. Sexual morph: Unknown. Asexual morph: Leaf-blotch symptoms on living leaves and on young, green stems. Colonies amphigenous, punctiform to effuse, loose to dense, caespitose, brown, villose. Mycelium immersed, subcuticular to intraepidermal; hyphae sparingly branched, septate, at times with swellings and constrictions, swollen cells up to 13 µm diam., subhyaline to pale brown, smooth, walls thickened, hyphae at times aggregated; in vitro mycelium initially immersed, becoming superficial, branched, pluriseptate, frequently constricted at septa and with swellings and constrictions, hence irregular in outline, smooth to verruculose or irregularly rough-walled, roughly verruculose with discrete large warts. Semi-macronematous conidiophores formed on leaf-blotches solitary or in small, loose groups, arising from internal hyphae or swollen hyphal cells, erumpent through the cuticle, occasionally emerging through stromata, erect, straight to somewhat flexuous, oblong, cylindrical, usually unbranched or occasionally branched, slightly attenuated towards the apex, septate, septa often dense, not constricted, pale to medium brown, sometimes paler towards the apex, smooth, thick-walled, wall often with two distinct layers, regularly somewhat inflated at the very base, up to 14 µm diam., occasionally proliferating enteroblastically; in vitro conidiophores arising laterally from plagiotropous hyphae or terminally from ascending hyphae, the latter usually appearing more filiform than those arising laterally from plagiotropous hyphae, erect, straight to slightly flexuous, cylindrical-oblong, not geniculate, usually unbranched, rarely with a short lateral prolongation near the apex, slightly attenuated towards the apex, septate, pale to medium brown or olivaceous-brown, smooth to asperulate, walls somewhat thickened. Conidiogenous cells integrated, terminal or intercalary, subcylindrical, proliferation sympodial, with one to several conidiogenous loci, subdenticulate or denticulate, protuberant, terminally broadly truncate, unthickened or almost so, somewhat darkened-refractive. Conidia catenate, in simple or branched chains, polymorphous, small conidia globose, subglobose, broadly obovoid, aseptate, pale to medium brown, smooth, intercalary conidia limoniform, ellipsoid-fusiform, oblong, 0–2-septate, medium brown, smooth to minutely verruculose or irregularly rough-walled, large conidia ellipsoid, oblong-cylindrical, ampulliform, 0–5-septate, medium brown, smooth to minutely verruculose or irregularly rough-walled, walls somewhat thickened, hila truncate, 1–3 µm wide, unthickened or almost so, somewhat darkened refractive; occasionally with microcyclic conidiogenesis; in vitro numerous, polymorphous, catenate, in loosely branched chains, small conidia globose, subglobose, or obovoid, aseptate, intercalary conidia limoniform to ellipsoid-fusiform, 0–1-septate, large conidia ellipsoid to cylindrical oblong, pale to medium brown, asperulate, minutely verruculose to irregularly rough walled, walls thickened, hila usually short denticle-like, protuberant, truncate, unthickened or almost so but generally darkened refractive; with infrequent microcyclic conidiogenesis. Characters of the periconioid morph: Macronematous conidiophores formed on faded or dead stems in late autumn, winter or after overwintering. Mycelium immersed, subcuticular to intraepidermal; hyphae at first sparsely branched, septate, not constricted at the septa, becoming swollen and wider, up to 11 µm wide, often branched, pale to medium olivaceous-brown, walls thickened, forming loose to dense hyphal aggregations; in vitro mycelium immersed to superficial, loosely branched, pluriseptate, generally without swellings and constrictions, sub hyaline to medium brown or olivaceous brown, almost smooth to asperulate or irregularly rough-walled, in mature colonies on PDA up to 10 µm wide, occasionally single hyphal cells markedly swollen, mainly at the base of conidiophores, at times covered by a slime coat or enveloped in a polysaccharide-like layer. Stromata well-developed, large and expanded, composed of a single to several layers of swollen pale to medium brown stromatic cells. Conidiophores solitary or in loose groups, arising from swollen hyphal cells or stromata, erumpent through the cuticle, erect, straight, rigid to slightly flexuous, composed of a subcylindrical stipe, slightly attenuated towards the apex, 5–15 µm just below the branched head, pluriseptate, not constricted at the septa, young conidiophores pale medium olivaceous-brown, later medium to usually dark brown, at times slightly paler at the distal end, smooth or almost so, often appearing somewhat granular, roughened, walls distinctly thickened, apex with a roughly sub globose to ovoid head, composed of dense branchlets and ramoconidia, primary branchlets close to the apex and below the first and sometimes second and third septa, solitary, in pairs or small verticils, appressed against the stipe or somewhat divergent, subcylindrical to ellipsoid-oval, aseptate, rarely uniseptate, pale olivaceous to dark brown, in vitro conidiophores initially micro and semi macronematous, then progressively macronematous as colonies age, arising laterally from plagiotropous hyphae or terminally from ascending hyphae, sometimes also from swollen hyphal cells; micronematous conidiophores filiform, narrowly cylindrical-oblong, unbranched, septate, septa often appear to be darkened, pale to pale medium olivaceous-brown, asperulate, walls slightly thickened; semi-macronematous conidiophores often resembling those formed by the leaf-blotching (cladosporioid) morph on the natural host, subcylindrical to cylindrical-oblong, straight to slightly flexuous, unbranched, rarely branched, slightly attenuated towards the apex, septate, medium brown, closely verruculose to irregularly rough-walled, walls more or less thickened; macronematous conidiophores formed in older cultures on SNA, PDA and MEA but more conspicuous on PDA and MEA, similar to those formed by the stem-rotting morph (i.e. the periconioid morph, in planta), comprising of a long unbranched stipe and a subglobose head, but in culture the heads are often more loosely branched than on the natural substratum, not always forming a compact head, attenuated towards the apex, 4–8 µm just below the branched upper part, slightly swollen at the base, septate, medium to very dark brown, minutely verruculose, walls distinctly thickened, two distinct wall layers visible, 1–2 µm thick. Conidiogenous cells holoblastic, integrated, terminal, intercalary or even discrete, ellipsoid to cylindrical or doliiform, subdenticulate, proliferation sympodial, multilocal, conidiogenous loci truncate, flat, unthickened, 1–3 µm wide, somewhat darkened-refractive; in culture conidiogenous loci appearing to be somewhat thickened and distinctly darkened-refractive. Conidia catenate, in long, branched chains, straight, subglobose, aseptate, or ellipsoid-ovoid, 0(–1)-septate, pale olivaceous to olivaceous-brown, smooth to verruculose (under the light microscope), hila flat, truncate, unthickened, not darkened, but somewhat refractive; in vitro conidia numerous, catenate, formed in long, branched chains, small conidia globose to subglobose, aseptate, intercalary ones ellipsoid-ovoid, 0(–1)-septate, secondary ramoconidia ellipsoid to cylindrical-oblong, 0–2-septate, sometimes slightly constricted at the septa, medium olivaceous-brown, verruculose or irregularly rough-walled, walls slightly to distinctly thickened, hila more or less protuberant, sub denticulate to denticulate, in small and intercalary conidia, in secondary ramoconidia unthickened or somewhat thickened, darkened-refractive; occasional microcyclic conidiogenesis (adapted from Schubert et al. 2007).

Type species: Graphiopsis chlorocephala (Fresen.) Trail

Notes: Graphiopsis is characterised by brown, anastomosing mycelium, micro- to semi-macronematous conidiophores, holoblastic, determinate conidiogenous cells and dry, acrogenous conidia. Berkeley and Broome (1859) established the genus Haplographium and accommodated one new species H. delicatum and two other existing species Graphium tenuissimum Corda and Periconia chlorocephala Fres. Grove (1885) added another species Haplographium bicolor to the genus. Trail (1889) carefully examined Haplographium bicolor and Periconia chlorocephala and concluded that the two species are not congeneric with one another and neither with Haplographium delicatum. Hence, Trail (1889) proposed the genus Graphiopsis to include species previously allocated in Periconia of which P. cholorocephala Fresen. was considered as the type. Graphiopsis resembles Periconia in having catenate conidia and generally some stout brown branches near the tip of the erect conidiophores but differs in the brown conidia and mode of branching at the tip of the fertile hyphae. Mason and Ellis (1953) proposed the new combination Cladosporium chlorocephalum based on a specimen collected on dead stems of peony. Schubert et al. (2007) assigned C. chlorocephalum to a new genus Dichocladosporium based on the morphology of the conidiogenous loci which differs from the characteristically coronate scars of members of Cladosporium and ITS sequences which showed that C. chlorocephalum is distinct from Cladosporium sensu stricto. Braun et al. (2008) regarded Dichocladosporium as a synonym under Graphiopsis however Graphiopsis is the older and valid name for the genus Dichocladosporium. Graphiopsis is a distinct genus in Cladosporiaceae but molecular data of more species is needed to strengthen this placement. Molecular markers available for Graphiopsis are ITS, LSU, SSU and RPB2.

Graphiopsis

Recent News

Recent Genus

Recent Species

About Dothideomycetes

Contact