This common endemic fungus is associated with a leaf spot on Coprosma spp

Type: Foliicolous Fungi; Description: Ascomata perithecial, gregarious, subepidermal, globose conical, black, 0.1 mm in diameter, papillate; on distinctive, irregularly-shaped grey leaf spots with reddish margins, up to 10 mm across, on lower surfaces of leaves. Asci saccate-cylindrical, 36–44 × 8–11 μm. Ascospores ellipsoid to clavate, 1-septate, 14–16 × 2–3 μm, smooth, hyaline. Conidiomata pycnidial, ostiolate. Conidia fusoid to oblong-fusoid, ends tapering, 5–6 × 3–4 μm, smooth, hyaline.

Distribution: Northland, Auckland, Coromandel, Taranaki, Taupo, Rangitikei, Wanganui, Wellington, Nelson, Buller, Mid Canterbury, South Canterbury.; 1st Record: Sydow (1924).

Significance: Of no significance.; Host(s): Coprosma foetidissima, C. grandifolia, C. lucida, C. robusta, C. tenuifolia.

Maculae distinctissimae, amphigenae, orbiculares, ½-1 cm diam., fuscidulae, linea elevata atro-purpurea cinctae, mox centro albicantes; perithecia hypophylla, in centro macularum densissime coacervata, subepidermalia, globoso-conoidea, 90-120 µ diam., papillula tantum per epidermidem prominula, parenchymatice e cellulis obscure brunneis 7-9 µ diam. contexta; asci fasciculati, sessiles vel subsessiles, cylindraceo-saccati, ad apicem obtusi, crasse tunicati, octospori, 36-44 x 8-11 µ, aparaphysati; sporae distichae, angustissime clavulatae, medio vel circa medium septatae, non constrictae, rectae, superne semper obtuse rotundatae, deorsum plerumque leniter attenuatae, 14-16 x 2-2½ µ, hyalinae, cellula superiore fere semper leniter latiore; pycnidia simul praesentia peritheciis immixta, eadem fere magnitudine, e cellulis dilutioribus et minoribus 4-6 µ diam. contexta, poro rotundo ca. 10-12 µ lato pertusa; sporulae fusoideae vel oblongo-fusoideae, plerumque utrinque leniter attenuatae, rarius rotundatae, continuae hyalinae, 5-6 x 1½-2½ µ, sporophoris non visis.

Von der folgenden Mycosphaerella spissa Syd. ist die Art völlig verschieden. Die Perithezien vermischt mit den Pykniden bedecken in dichten Haufen das Zentrum der Blattflecke, und an den pilzbefallenen Stellen ist das Blattparenchym in seiner ganzen Dicke dicht mit braunen ca. 3 µ breiten Myzelhyphen, die sich oft der Länge nach vereinigen oder knäuelförmig zusammenballen, durchzogen.

Hab. in foliis Coprosmae spec., in horto botanico, Wellington, 18. 10. 1920, leg. E. H. Atkinson (no. 970).