Petrakina mirabilis Cif., Annls mycol. 30(3/4): 225 (1932).
Type: NY 00936794.
Epiphytes, saprobic on the surface of leaves appearing as blackened spots. Superficial hyphae not observed. Sexual state: Thyriothecia 470–481 diam×78–84 high μm (x= 475×80 μm, n=5), superficial, scattered, central ostiole present as star-like opening. Upper wall comprising brown walled complexly arranged hyphae, branched at margin, poorly developed at the base. Hamathecium of 3 μm, septate, pseudoparaphyses, anastomosing between and above the asci, embedded in a gelatinous matrix. Asci 61–77×23–26 μm (x = 64×24 μm, n=10), 6–8-spored, rarely 8-spored, bitunicate, fissitunicate, clavate to broadly cylindrical, short pedicel or sometimes absent, apically rounded, ocular chamber absent. Ascospores 22–27×8–11 μm (x = 24×10 μm, n=10), overlapping bi-seriate, oblong to fusoid, muriform, with 4–5- transverse septate, 1–2 vertical septa, rounded and narrow at each both ends, constricted at centre, hyaline to pale brown when immature and brown at maturity, smooth-walled. Asexual state: Unknown.
Material examined: DOMINICAN REPUBLIC, Santiago Province, Rio Yaque, Valle del Cibao, on surface of leaves of
Typha latifolina (Typhaceae), 22 February 1931, E.L Ekman no 4131 in Herb. R. Ciferri (NY 00936794, syntype).
Fig. 1 Petrakina mirabilis (syntype). a–c Herbarium packages. d Herbarium specimen. e Thyriothecia on substrate. f Thyriothecia with ostiole with star-like opening. g Section through thyriothecia. h Peridium at periphery. i Upper wall of thyriothecium. j Hamathecium. k Immature ascus. l Mature ascus. m Immature ascospores. n Mature ascospores. Scale bars: f, g=100μm, h–n=20μm
