Xylochrysis guttulata Y. Xiao. & Jian K. Liu, 2025

Xiao, Yue & Liu, Jian-Kui, 2025, Xylochrysis guttulata sp. nov., associated with Camellia sinensis in Sichuan Province, China, Phytotaxa 698 (1), pp. 35-42 : 38-40

Xylochrysis guttulata Y. Xiao. & Jian K. Liu , sp. nov. ( FIGURE. 2 )

MycoBank number MB 858492

Etymology: —The species epithet “ guttulata ”from the Latin guttulatus, referring to the presence of large guttules in the ascospore.

Holotype: —HKAS 135169.

Saprobic on dead twigs of Camellia sinensis . Sexual morph: Ascomata 194–271 μm diam. × 177–246 μm high (= 212 × 213 μm, n = 10), scattered or aggregated in small groups, with a solitary locule, semi-immersed, subglobose to pyriform, nonstromatic, glabrous, lacking a peridium of golden yellow cells encircling the basal venter, short ostiolate. Ostiole 37–50 μm long, 34–60 μm diam. (= 44 × 43 μm, n = 10), central, black, papillate, cylindrical to narrowly canalled, with dark pigmented cells in the neck, glabrous, lined with hyaline periphyses. Peridium leathery to fragile, multi-layered, outer layers 9–39 μm thick, carbonized, composed of dark brown, polyhedral cells of textura prismatica with opaque walls, inner layers 4–15 μm thick, textura prismatica, composed of multiple rows of thin-walled, hyaline, flattened cells. Hamathecium 4–5 μm wide (= 4 μm, n = 30), numerous filamentous, narrowly cylindrical to filiform, branched paraphyses, not embedded in a gelatinous matrix, hyaline, septate, guttulate. Asci 70–110 × 3.5–4.5 μm (= 95 × 4 μm, n = 30), 8-spored, long cylindrical, rounded at apex, with slender stipe, clear apical apparatus, more clearly visible in Xylochrysis guttulata , with a bulbous long pedicel, tapering to the bulbose base. Ascospores 4–7 × 2–3.5 μm (= 6 × 3 μm, n = 30), uniseriate, hyaline, aseptate, lanceolate to oval, one guttule at each end, without appendages and mucilaginous sheath. Asexual morph: Undetermined.

Culture characteristics: —Ascospores germinating after 24 h on PDA. Colonies growing on PDA 15–20 mm diam. after 30 d at 25 °C, brown, irregular, flat, lobate, with whitish aerial hyphae in the middle, green uneven.

Material examined: — CHINA. Sichuan Province: Leshan City, Muchuan County, Miaoping Village, 28°54’37''N, 103°52’12''E,elevation 537m, on dead twigs of Camellia sinensis , 13th October2023,Y.Xiao, (HKAS 135169 holotype), ex-type living culture CGMCC 3.27589; Ibid., Leshan City, Muchuan County, Lijiashan, 28°89'18''N, 103°83'46''E, elevation 1129 m, on dead twigs of Camelliae sinensis , 4th November 2022, Y.H. Lu, (HUEST 24.0214).

Notes: — Xylochrysis is a holomorphic genus typified by X. lucida (Liu et al. 2012; Reblova et al. 2012). To date, only two species, X. lucida and X. aquatica , have been described in this genus. Phylogenetic analyses by Song et al. (2023) confirmed that these two species form a sister relationship and represent a distinct lineage within Woswasiaceae (100% ML; 1.00 PP). Xylochrysis guttulata resembles X. lucida in having immersed ascomata, short ostiolar necks, and hyaline, ellipsoidal ascospores (Réblová et al. 2014). However, X. guttulata can be distinguished by its scattered, smaller ascomata (194–271 × 177–246 μm vs. 350–500 × 350–500 μm) and larger asci (70–110 × 4–5 μm vs. 59–70 × 4–4.6 μm), the absence of a surrounding layer of pigmented cells, and a shorter, less prominent ostiolar neck. Phylogenetic analyses support X. guttulata as a distinct species within Woswasiaceae .Additionally, nucleotide sequence comparisons between X. guttulata (CGMCC 3.27589) and X. lucida (CBS 135996) revealed differences of 10/581 bp (2%) in ITS and 8/990 bp (1.5%) in rpb2. Based on both morphological characteristics and phylogenetic evidence, Xylochrysis guttulata is introduced as a novel species.

Figures

FIGURE 2. Xylochrysis guttulata (HKAS 135169 holotype). a–d Apperance of ascomata on the host surface. e, f Vertical section of ascomata. g Peridium. h Hamathecium. i–l Asci. m–q Ascospores. r Germinating ascopore. s Colony from above. t Colony from below. Scale bars: e = 50 μm, f, i–l = 20 μm, g, h = 10 μm, m–r = 5 μm.