Plenodomus lingam (Tode: Fr.) Höhn., Sitzungsber. Kaiserl.Akad.Wiss., Math.-Naturwiss. Cl., Abt. 1.120: 463. 1911

Saprobic or parasitic on stems and leaves of herbaceous or woody plants in terrestrial habitats.Sexual morph: Ascomata 200–250 μm high × 300–500 μmdiam., solitary, scattered or in small groups, semi-immersed to immersed, subglobose to depressed globose, broadly or narrowly conical, small- to medium-sized, dark brown to black, smooth, ostiolate. Ostiole apex with a conical, welldeveloped dark brown to black papilla, ostiolar canal filled with periphyses. Peridium 8–12 μm wide at sides, composed of two layers, scleroplectenchymatous, outer layer composed of small thick-walled cells of textura angularis, surface heavily pigmented, thinner at the apex, wide at sides, inner layer composed of subhyaline or light brown cells of textura angularis, cells near the base comparatively larger. Hamathecium comprising 1.5–3 μm (x̅ = 2.5 μm, n = 10) wide, long, septate, cellular pseudoparaphyses, branching and anastomosing, embedded in a gelatinous matrix. Asci 90–110 × 10–12 μm, 8-spored, bitunicate, fissitunicate, cylindrical, rounded at the apex, short pedicel with an ocular chamber. Ascospores 35–70 × 5–8 μm, uni-seriate, partially overlapping, yellowish brown, cylindrical to ellipsoidal, 5-septate, not or slightly constricted at each septum, guttulate, lacking a mucilaginous sheath. Asexual morph: Coelomycetous, with two types of Conidiomata. Type 1: 150–350 μm wide, solitary, scattered or in small groups, erumpent to superficial, subglobose or flask-shaped, with a broad base, mostly black, ostiolate. Ostiole apex with a long neck and welldeveloped poroid papilla. Type 2: 300–700 μm wide, solitary, scattered or in small groups, erumpent to superficial, mostly subglobose, ostiolate. Ostiole slightly papillate with a narrow pore or opening via a rupture.Conidiomata wall composed of several layers with thick-walled cells of textura angularis, surface heavily pigmented (often termed scleroplectenchyma). Conidia3–5 × 1–2 μm,hyaline, aseptate, ellipsoidal to subcylindrical, rarely with two small polar guttules (Sivanesan 1984).

Fig.Plenodomus rabenhorstii(redrawn from Leptosphaeria maculansin Sivanesan 1984, Fig 269).a. Ascoma. b. Ascus and ascospores. c. Conidioma.d. Conidiogenous cells. e. Conidia. Scale bars: a = 10 µm, b = 25 µm

Notes: The genus Plenodomus was introduced by Preuss (1851) and is typified by P. rabenhorstii. The combination P. lingam as published by Höhnel (1911) was favoured over P. rabenhorstii Preuss (1851) by Boerema & van Kesteren (1964) because the type material of P. rabenhorstii had been lost during the World War II. Therefore,P. rabenhorstii was treated as a nomen dubium by De Gruyter et al. (2013). We follow Höhnel’s (1911) proposal by treating Plen. lingamas the type species for the genus Plenodomus. The asexual and sexual connection between the type of Plenodomus,P. lingam and its sexual morph Leptosphaeria maculans has been proven by single spore isolation (Boerema and van Kesteren 1964). This was also confirmed by molecular data by De Gruyter et al. (2013)