Flora of New Zealand Series

=Strigula complanata (Fée) Mont. in R. de la Sagra, Hist. Phys. Cuba Bot. Pl. Cell. 2: 140 (1842).

≡Phyllocharis complanata Fée, Essai crypt. écorc: XCIX (1824).

Description : Thallus foliicolous, subcuticular, effigurate, rounded to irregular, 2–5(–15) mm diam., formed of linear lobes, 0.05–0.1 mm wide, usually completely confluent but distinct (without black margins), lobes sometimes discrete at thallus margins or centrally, often with white, tapering hairs (100–250 μm long, 10–15 μm wide), pale green-grey to green-white (white when moribund), glossy; 20–40 μm thick, dominated by photobiont layer, without a prothallus. Photobiont Cephaleuros, cells ±rectangular to subirregular, 20–40(–54) × 10–16 μm, forming continuous plates. Perithecia 0.1–0.2(–0.25) mm diam., 100–150 μm tall, at first almost completely immersed in thallus, becoming convex, the covering thalline tissue irregularly rupturing to expose the black, shining involucrellum. Involucrellum 10–15 μm thick, brownish black to black. Exciple colourless to pale-brownish. Centrum subapplanate to globose. Paraphyses simple, c. 1 μm thick. Periphyses indistinct. Asci obclavate to almost fusiform, 45–70 × 10–15 μm. Ascospores 8 per ascus, biseriate, 3-septate (rarely 1-septate), fusiform to subbacillar, one end obtuse the other acute, not constricted at septa, (12–)15–24 × 3.5–6 μm. Pycnidia 0.1 mm diam., almost completely immersed, to partly exposed, black; macroconidia 3–7(–9)-septate, ±filiform, (25–)30–65 × 2.–2.5 μm. Microconidia not seen.

N: Auckland (Waitakere Ra.). On leaves of Alectryon excelsum and Beilschmiedia tawa (Bartlett 1988). Known also from the United States, Mexico, Central and South America, East and South Africa, Madagascar, Sri Lanka, Java, Philippines, New Caledonia, Cocos Is, Tonga and Australia (Santesson 1952; Lücking 1992; Lücking & Lücking 1995; Farkas & Sipman 1997; Elix & McCarthy 1998; McCarthy 2003c, 2006; Farkas 2004).

Cosmopolitan

Illustrations : Fée (1824: tab. II figs 3, 7); Ward (1883: pls 18–21); Santesson (1952: 191, fig. 29 – as Strigula complanata); Lücking (1992: 46, fig. 11G – as Strigula complanata).

Strigula orbicularis is characterised by: the foliicolous habit; the 3-septate ascospores and the filiform conidia. This places the species in a rather isolated position among foliicolous members of the genus (Lücking 1992: 49).