Coniochaeta acaciae Samarakoon, Gafforov & K.D. Hyde, Samarakoon et al., Phytotaxa 336(1): 49 (2018)

Index Fungorum number: IF 553912

Saprobic on dead trunk and branches of Betula pendula. Asexual morph: See Samarakoon et al. (2018). Sexual morph: Ascomata 250–300 μm wide, 260–350 μm high, solitary to gregarious, semi-immersed to superficial, globose to ovoid, carbonaceous, papillate. Peridium 27–36 μm, two-layered, inner layer comprising of hyaline to subhyaline cells of textura prismatica, outer layer comprising of closely packed, thick-walled, brown cells of textura intricata. Ostiolar necks 1.1–1.6 × 0.2–2.5 μm (x̅ = 1.2 × 2.2 µm, n = 10), papillate to cylindrical, filled with periphyses. Paraphyses filiform, septate, hyaline. Asci 87–110 × 8–10 μm (x̅ = 87.7 × 9.2 µm, n = 10), 8-spored, unitunicate, cylindrical, with small J- apical ring, pedicellate. Ascospores 14–16 × 7–8 μm (x̅ = 14.5 × 7.6 µm, n = 10), uniseriate, slightly laterally compressed, ellipsoid to ovoid, dark brown, with straight germ slit across the entire length, smooth-walled, multiguttulate, without sheath or appendages

Culture characteristics – Colonies on MEA, reaching 20–30 mm diam. after 4 weeks at 25 °C, circular, surface rough, entire edge, in the middle orange, on the edge yellowish red, diffuse margin with light orange mycelium, reverse yellowish edges, grayish orange at the center, radiating, effuse and azonate.

Material examined – Ukraine, Donetsk region, Donetsk City, Donetsk Botanical garden, steppe community, on dead twigs and branches of Betula pendula (Betulaceae), 18 May 2017, T. Bulgakov (MFLU 17-2473); living cultures MFLUCC 18-0776.

GenBank numbers – LSU: MT501618, ITS: MT498810, SSU: MT498798, TEF1-α: MT503199.

Known distribution (based on molecular data) – Uzbekistan (Samarakoon et al. 2018), Ukraine (this study).

Known hosts (based on molecular data) – Acacia sp. (Samarakoon et al. 2018), Betula pendula (this study).

Notes – Our new isolate MFLUCC 18-0776 is morphologically similar and phylogenetically related to Coniochaeta acaciae (MFLUCC 17-2298), but collected from a different host and geographical location. Coniochaeta acaciae was reported from Uzbekistan on branches of Acacia sp. (Fabaceae) (Samarakoon et al. 2018), while our collection is from Ukraine on Betula pendula (Betulaceae). The phylogenetic placement of our strain (MFLUCC 18-0776) is shown.

Figure 1. Coniochaeta acaciae (MFLU 17-2473, new host and geographical record). a, b Appearance of ascomata on host surface. c Vertical section through the ascoma. d Peridium. e Hamathecium. f–h Asci. i–n Ascospores. o Germinated ascospore. p, q Culture characteristics on MEA (p: above view; q: reverse view). Scale bars: a = 2000 μm, b = 1000 μm, c–e = 10 μm, f–h = 20 μm, i–n = 10 μm, o = 30 μm.