Phaeodothis tricuspidis Syd. & P. Syd., Annls

Tennakoon, Danushka S., Kuo, Chang-Hsin & Hyde, Kevin D., 2020, Multi-locus phylogeny reveals Phaeodothis mori sp. nov. (Didymosphaeriaceae, Pleosporales) from dead leaves of Morus australis, Phytotaxa 428 (3), pp. 241-254 : 248

Phaeodothis tricuspidis Syd. & P. Syd., Annls mycol. 2(2): 166 (1904)

Index Fungorum Number: IF 185110; Facesoffungi number: FoF 00060, FIGURE 3

Saprobic on dead wood or grasses. Sexual morph: Ascomata 220–300×120−180 μm (x = 255×137 μm, n=10), immersed to nearly superficial under clypeus, scattered to gregarious, subglobose to hemispherical, dark brown to black, papillate. Papilla black, with pore-like ostioles, ostiolar canal filled with periphyses. Peridium 15−25μm (x =23μm, n=20) wide, comprising several layers of hyaline to light brown, compressed cells of textura angularis , fusing and indistinguishable from the host tissues. Hamathecium of 2−4 μm wide (x = 2.6 μm, n=20), aseptate, cellular pseudoparaphyses often embedded in a gelatinous matrix. Asci 50 − 80 × 7−12 μm (x = 69 × 10 μm, n = 20), 8-spored, bitunicate, fissitunicate, cylindrical, short pedicellate, apically rounded with a minute ocular chamber. Ascospores 14−17 × 4−5μm (x = 15.8 × 4.5 μm, n=30), unit to biseriate and partially overlapping, fusiform with rounded ends, olivaceous brown, 1-septate, constricted at the septa, smooth-walled. Asexual morph: unknown.

Material examined: — ARGENTINA, San José, Salta, on leaves of Tricuspis latifolia Griseb. ( Poaceae ), 12 February 1873, P.G. Lorentz (SF125876, holotype).

Notes:— Phaeodothis tricuspidis was introduced by Sydow and Sydow (1904), from living leaves of Tricuspis latifolia Griseb. ( Poaceae ) and they assumed it to be very close to those of Dothidella , but differ in having dark ascospores ( Malloch & Mallik 1998). Phaeodothis mori can be distinguished from the type species, P. tricuspidis in having smaller ascomata (100–150 × 80–130 μm) and yellowish brown, ascospores (10.5–12.5 × 3–4 μm) with mucilaginous sheath, whereas P. tricuspidis has larger ascomata (220–300×120−180 μm) and olivaceous brown, ascospores (14−17 × 4−5μm) lacking a mucilaginous sheath. As well as, Phaeodothis tricuspidis has been recorded from dead grass stems ( Poaceae ), which is a monocot; whereas P. mori was recorded from the decaying leaves of Morus australis ( Moraceae ), which is a dicot. However, molecular data are essentially needed to clarify phylogenetic placement of type species.

Figures

FIGURE 3. Phaeodothis tricuspidis (SF125876, holotype) a. Herbarium packet and specimen. b. Ascomata on host. c. Close up of ascoma. d, e. Sections through ascomata. f. Peridium comprising hyaline compressed cells. g–j. Mature and immature asci surrounded by pseudoparaphyses. k–n. ascospores. Scale bars: c = 1000 µm, d, e = 100 µm, f = 20 µm, g–j = 30 µm, k–n = 5 µm.