Apiculospora yuccae Tibpromma, sp. nov. (Fig. 3)

MycoBank number: MB 558360; Index Fungorum number: IF 558360; Facesoffungi number: FoF 10416

Etymology: Name reflects the host genus Yucca.

Holotype: HKAS 115529

Saprobic on dead leaves of Yucca gigantea. Sexual morph: Undetermined. Asexual morph: Conidiomata 145–175 μm diam., 125–155 μm high (x̅ = 160.99 × 137.6 μm, n=5), immersed, solitary, scattered, unilocular, subglobose, black dots, masses of spores all over the leaf surfaces of the host. Conidiomata wall 15–25 μm, composed of thick-walled, orange-brown to brown cells of textura angularis; inner cell layers thin-walled, almost reduced to a conidiogenesis region. Conidiophores reduced to conidiogenous cells. Conidiogenous cells 1.5–3 × 3–10 μm, subcylindrical to ovoid, enteroblastic, with percurrent proliferation, hyaline, smooth-walled. Hamathecium 1–3.5 μm wide, unbranched, guttulate, septate, hyaline. Conidia 5–25 × 15–25 μm (x̅ = 8.93 × 22.16 μm, n = 40), subcylindrical to ellipsoid, slightly curved, conical at apex, aseptate when immature and later become 1-septate, sometimes a dark band at septum, sometimes constricted at septum, hyaline to pale brown when immature and later dark brown, guttulate, thick- walled non mucilaginous.

Culture characteristics: culture on PDA, colonies slow growing, circular, spreading, flattened, flossy, smooth with entire edge, brown; reverse brown.

Material examined: China, Yunnan Province, Kunming Institute of Botany garden (Camellia garden), dead leaves of Yucca gigantea Lem. (Asparagaceae), 7 May 2020, Saowaluck Tibpromma, ST11 (HKAS 115529, holotype); ex-type living cultures KUMCC 21-1812.

GenBank accession numbers: LSU: MW881143; ITS: MW881159.

Notes: Our collection fits with the characteristics of Apiculospora in having subcylindrical to ellipsoid conidia with a dark band at septum (Wijayawardene et al. 2016, Ekanayaka et al. 2019, Karunarathna et al. 2021). In the phylogenetic tree, Apiculospora yuccae is clearly distinct from A. spartii (MFLU 15-3556, MFLU 18-1812, MFLU 18-1813) with 99% ML, and 1.00 BYPP statistical support (Fig. 2). Apiculospora yuccae can be distinguished from A. spartii by its larger conidia (5–25 × 15–25 μm) with conical apcies, whereas A. spartii has smaller conidia (17–25 × 8–11 μm) with truncate bases and apices with apiculi (Wijayawardene et al. 2016).

Figure 3 – Apiculospora yuccae (HKAS 115529, holotype). a Conidiomata on dead leaves of Yucca gigantea. b Longitudinal section of conidiomata. c, d Different stages of developing conidia attach to conidiogenous cells. e–h Conidia. i, j Colony characteristics on PDA medium (after 14 days old culture). Scale bars: b, e, f = 20 μm, c, g, h = 5 μm, d = 10 μm.