Stigmidium schaereri
≡*Sphaeria schaereri A.Massal., Sulla Lecidea Hookeri: 8 (1853).
Description : Lichenicolous on thallus of host (Pseudocyphellaria, Xanthoria), vegetative hyphae colourless. Perithecia globose, 60–125 × 55–115 μm, solitary to crowded, subimmersed to sessile; wall 10–20 μm thick, brownish in upper parts, paler below. Periphyses and pseudoparaphyses, 6–10 × 1.5–2.5 μm. Asci broadly cylindrical to clavate, 30–45 × 12–15 μm, 8-spored. Ascospores colourless, ellipsoidal to oblong with rounded apices, not constricted at septum, sometimes with 2 vacuoles per cell, (10–)12–15.5(–18) × 3–4(–5) μm.
S: Canterbury (Banks Peninsula, Otepatotu Scenic Reserve). On Pseudocyphellaria rufovirescens"Growing on base of Podocarpus totara in remnant cool temperate forest on moderate slope, dominated by Podocarpus", 720 m. 3.iii.1985, J.A. Elix 18991 & J. Johnston [Elix: Lichenes Australasici Exsiccati Fasc. 8. No. 191, December 1989], Otago (Saddle Hill, collected by W.L. Lindsay 26.x.1861), Southland (Lake Gunn). St: (Half Moon Bay [Josephine Tilden, South Pacific Plants No. 328 – BM]). Known also from Great Britain, Europe, and Scandinavia (Diederich 1986; Santesson 1993; Hawksworth 2003; Santesson et al. 2004).
Cosmopolitan
Hosts : Pseudocyphellaria homoeophylla, P. rufovirescens, Xanthoria parietina (Kondratyuk & Galloway 1994: 29). Elsewhere on Lecidella elaeochroma (Diederich 1986).
Illustration : Triebel (1989: 74, fig. 7E).
* Stigmidium schaereri is characterised by: the lichenicolous habit; perithecia immersed in apothecia of host (species of Pseudocyphellaria and Xanthoria parietina); and 1-septate ascospores, (10–)12–15.5(–18) × 3–4(–5) μm.
