Dothideomycetes » Dothideomycetes, genera incertae sedis » Harknessiella

Harknessiella purpurea

Harknessiella purpurea (W. Phillips & Harkn.) Sacc., Syll. fung. (Abellini) 8: 845 (1889)                        Fig. 54

º Phillipsiella purpurea W. Phillips & Harkn., Bull. Calif. Acad. Sci. 1(no. 1): 23

Index Fungorum number: IF147107; Facesoffungi number: FoF 06245

Saprobic on lower surface of Garrya elliptica leaves. Sexual morph: Ascomata 315–417 µm high, × 479–542 µm diam., scattered, solitary, superficial, globose to subglobose, easily removable from the host surface, consist of setae, glabrous, ostiolate at centre, with minute papilla lined with short, brown, aseptate periphyses. Peridium 18–28 µm wide, thin-walled, of equal thickness, composed of several layers of small, flattened, brown to dark brown cells of textura angularis. Hamathecium 3–4 µm wide composed of dense, 2–3 µm wide, broad filamentous, distinctly septate, anastomosed pseudoparaphyses, embedded in a hyaline gelatinous matrix. Asci 79–103 µm × 9–11 µm (x̅ = 92.6 × 9.1 µm, n = 10), 8-spored, bitunicate, fissitunicate, cylindrical to cylindric-clavate, short pedicellate, apically rounded, with an ocular chamber. Ascospores 17–21 µm × 3–4 µm (x̅ = 19.6 × 3.9 µm, n = 10), overlapping 1–2-seriate, hyaline, fusiform with rounded ends, 3-septate, slightly constricted at the central septum, smooth-walled. Asexual morph: Pycnidia 302358 µm × 485–502 µm (x̅ = 311.6 × 499.5 µm, n = 10), hypophyllous, dark brown to black, superficial sparsely scattered or sporadically distributed on surface of leaves, easily removable from the host substrate. Conidiophores straight or slightly curved, hyaline, reduced to conidiogenous cells. Conidiogenous cells holoblastic, percurrent, cylindrical to elliptical, septate, rough and thick-walled. Conidia 10–14 µm × 2–3 µm (x̅ = 12.8 × 2.6 µm, n = 10), hyaline to olivaceous-green, 2–3 septate, ellipsoidal to cylindrical, smooth-walled.

Material examined – USA, California, near Tamalpais, on lower surface of leaf of Garrya elliptica (Garryaceae), 8 July 1913, J.J Davis (C0170081F).

Economic significance – The genus Harknessiella causes yellow leaf spots on leaves of hosts (Saccardo 1889).