Gnomonia papuana
Gnomonia papuana Sivan. & D.E. Shaw
Sexual morph: Perithecia were globose, immersed, black, smooth, 120-280 µm broad with long necks protruding a little above the water surface in the petri dish. Necks cylindrical, straight or slightly curved, 440-1100 µm long, 15-66 µm wide, black, composed of dark brown septate hyphae 2-4 µm thick, running longitudinally in the shaft, less coloured towards the tip, and lined on the inside with hyaline periphyses. Asci obovoid, 19-27 (mostly 21-23) ´ 4-7.5 µm, unitunicate, 8-spored, with an apical ring apparatus which appears as two adjacent refractive areas each about 0,6 µm tall, from 0.6-1.2 µm from the tip, not staining blue in iodine. Ascospores arranged parallel to one another in the ascus, straight to slightly curved, cylindrical, slightly tapered to the rounded tip, slightly more tapered to the base, hyaline, one septate, guttulate, 17-23 ´ 0.9-1.2 µm. When stained in Giemsa after hydrolysis with N HCI at 60 DC, the ascospores showed one nucleus per cell. Asexual morph: Conidiophores wide spreading, verticillately branched, smooth-walled, septate, hyaline, 1.5-3 µm thick. The ultimate branches of the whorls consist of two cells, of which the smaller basal cell almost always possesses a smaller phialidic conidiogenous cell just below the septum separating the upper, longer phialidic conidiogenous cell. Occasionally two to three whorls arise as terminal phialides. Phialidic conidiogenous cells are hyaline, tapering towards the spore forming apex, 3-8.5(18) ´ 2-3 µm, Conidia are enteroblastic, produced in slanting oblique chains with their ends lying one over the other and these conidia sometimes occur in short chains when they are not fully detached from one another. Conidia are hyaline, slightly greenish in mass, smooth, fusiform, with more or less tapered ends, one-celled, guttulate, 4.5-7.5 ´ 1.5-2 µm, when stained with Giemsa after acid hydrolysis show one nucleus per conidium. (Description based on Sivanesan & Shaw, 1977)
Distribution: Papua New Guinea, on submerged leaves (Sivanesan & Shaw 1977).
Notes: Holotype IMI 197503. Sequence data is not available.
Fig. 1. 2. Gnomonia papuana. Detached perithecial neck from submerged substrate. 3. Immature perithecium from culture. 4. Tip of perithecial neck, stained with lactic fuchsin, median focus. 5. Terminal globule of asci extruded from the neck on drying, dispersing in water, unstained. 6. Surface view of tip of perithecial neck, stained in lactic fuchsin. 7. Asci: three stained with lactic fuchsin; one unstained showing apical ring apparatus of two refractive areas; three stained with Giemsa showing two nuclei per ascospore. 8. Ascospores: group and one ascospore stained with lactic fuchsin; three ascospores stained with Giemsa showing two nuclei per spore. 9. Conidia: a group and three conidia stained with lactic fuchsin; four conidia stained with Giemsa showing one nucleus per conidium. 10. Conidia developing from phialides, stained with lactic fuchsin. (Images grabbed from Sivanesan & Shaw 1977)
Fig 2. 12.[K1] Gnomonia papuana. Conidiophores. 13. Conidia. (Images grabbed from Sivanesan & Shaw 1977)
References
Cesati V, De Notaris G (1863) Schema di classificazione degle sferiacei italici aschigeri piu’ o meno appartenenti al genere Sphaeria nell’ antico significato attribuitoglide Persono. Commentario della Soc Crittogamologica Ital 1:177–420
Fallah PM, Shearer CA. 2001- Freshwater ascomycetes: new or noteworthy species from north temperate lakes in Wisconsin. Mycologia 93:566–602.
Luo ZL, Hyde KD, Liu JK, Maharachchikumbura SSN et al. 2019 – Freshwater Sordariomycetes. Fungal Diversity 99, 451–660.
Maharachchikumbura SSN, Hyde KD, Jones EBG, McKenzie EHC et al. 2016 - Families of Sordariomycetes. Fungal Diversity 79:1–317.
Senanayake IC, Jeewon R, Chomnunti P, Wanasinghe DN, et al. 2018 – Taxonomic circumscription of Diaporthales based on multigene phylogeny and morphology. Fungal Diversity 93:241–443.
Sivanesan A, Shaw DE. 1977 - Gnomonia papuana sp.nov with a sesquicilium conidial state. Trans Br Mycol Soc 68:85–90
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