Hemigrapha asteriscus
≡*Melanographa asteriscus Müll.Arg., Flora 65: 519 (1882).
Description : Lichenicolous. Ascomata usually rounded when young to distinctly stellate at maturity, sometimes also elongate or branched, up to 0.8 mm diam. Hymenium up to 35 μm tall. Paraphysoids in mature ascomata thin and indistinct, 0.5–1.5 μm wide, not or only slightly swollen between septa, apices somewhat thickened. Periphysoid-like cells abundant on some specimens, simple, c. 4–6 × 3–6 μm. Asci 8-spored, broadly clavate, 16.5–24.5 × 9.5– 14 μm. Ascospores 1-septate, 7.5–11.5 × 3.5–4.5 μm. Conidiomata intermixed with ascomata. Macroconidial conidiogenous cells shortly ampulliform, 3.5–5.5 μm diam., 4.5–5(–6) μm long. Macroconidia ellipsoidal sometimes slightly curved or narrower centrally, not or indistinctly truncate at base, (8–)8.5–10(–10.5) × 2.5–2.7(–3) μm. Microconidial conidiogenous cells subspherical to shortly ampulliform, 2–3 μm diam., 2–3.5 μm long. Microconidia narrowly ellipsoidal to rod-shaped, thin-walled, distinctly truncate at base, (4.5–)4.8–5.2 × 1.3–1.5 μm.
N: Gisborne (Ruapani Track near Waikaremoana, Urewera National Park). S: Nelson (St Arnaud Ra., Mt Arthur, Rough Creek near Maruia Springs), Westland (Cape Foulwind), Southland (Pourakino River). Also known from Switzerland, Tasmania, Brazil, Argentina, Chile and Brazil (Diederich & Wedin 2000: 207–208; Aptroot 2002e).
Cosmopolitan
Host : Commensalistic on species of Peltigera.
Illustrations : Diederich & Wedin (2000: 206, fig. 1A; 207, fig. 2A, B; 209, fig. 4A–G).
Exsiccati : Santesson (2001: No. 316).
* Hemigrapha astericus is characterised by: the lichen host (Peltigera); 8-spored asci; the presence of macroconidia and microconidia; and 1-septate ascospores, 7.5–11.5 × 3.5–4.5 μm.
