Splanchospora fulviconidia R. Yoshioka, Voglmayr & Kaz. Tanaka sp. nov.

Figs 5, 10 B, G

Etymology.

From the Latin fulvi, meaning tawny, in reference to the tawny conidia.

Diagnosis.

Splanchospora fulviconidia can be easily distinguished from other species by its large-sized, yellowish-brown conidia.

Type.

JAPAN • Ibaraki: Tsukuba, Kannondai, Forest Research and Management Organization, Arboretum 2, dead twigs of Tilia japonica (Miq.) Simonk., 27 Mar 2024, R. Yoshioka, Y. Kudo & K. Tanaka, RY 91 (holotype HHUF 30708, ex-type MAFF 248153 = culture RY 91).

Description.

Sexual morph. Ascomata pseudoperithecial, scattered, immersed, erumpent at the ostiolar neck, subglobose to depressed globose or ampulliform, 560–570 μm high, 500–600 μm diam, ostiolate. Ostiolar neck central, 90–120 μm long, 80–110 μm wide. Ascomatal wall 34–39 μm thick at the sides, composed of 4–5 layers of polygonal, 6–14.5 (– 17) × 4–7 μm, brown cells. Pseudoparaphyses 2.5–3.5 μm wide, septate, branched and anastomosed. Asci bitunicate, clavate, 162–212 (– 296) × 27.5–41 (– 44) μm (mean ± SD = 196.3 ± 23.0 × 34.1 ± 3.3 μm, n = 62), short-stalked (25–63 μm long, mean ± SD = 40.1 ± 11.5 μm, n = 11), 8 - spored, rarely 2 - or 6 - spored due to meiotic failure or stunted spores, with bi- to tri-seriate ascospores. Ascospores clavate-ellipsoid to fusoid, 34.5–45 × 14–20 μm (mean ± SD = 39.4 ± 2.4 × 17.1 ± 1.2 μm, n = 128), l / w = 1.9–3.0 (mean ± SD = 2.3 ± 0.3, n = 128), 1 - septate, with a submedian septum [0.54–0.62 (– 0.68), mean ± SD = 0.59 ± 0.02, n = 128), strongly constricted at the septum, pale brown to brown, smooth, with an entire sheath.

Asexual morph. Conidiomata pycnidial, scattered, immersed, subglobose to depressed globose or ampulliform, 460–490 μm high, 350–460 μm diam, ostiolate. Ostiolar neck central, 150–170 μm long, 100–110 μm wide. Conidiomatal wall 19–26 μm thick, composed of 4–5 layers of polygonal, 5–11 (– 12.5) × 2.5–5 μm, brown cells. Paraphyses 2.5–4 μm wide, septate, branched. Conidiophores absent. Conidiogenous cells annellidic, cylindrical to ampulliform, 11–17.5 (– 20) × 3–5 μm (mean ± SD = 15.6 ± 2.3 × 4.2 ± 0.6 μm, n = 11). Conidia ellipsoid to irregularly ellipsoid, 29.5–37 (– 38.5) × 15–19 μm (mean ± SD = 33.9 ± 1.9 × 17.0 ± 0.8 μm, n = 90), l / w = (1.7 –) 1.8–2.2 (– 2.3) (mean ± SD = 2.0 ± 0.1, n = 90), aseptate, pale to yellowish brown, becoming dark brown during senescence, smooth, with thick spore wall (2–3 μm).

Colonies on PDA (after 2 weeks) attaining a diam of 3.2–4 cm, white; reverse sienna; no pigment produced. In culture same coelomycetous asexual morph formed. Conidia 30.5–42 × 15–20 μm (mean ± SD = 36.2 ± 2.7 × 16.8 ± 1.0 μm, n = 150), l / w = (1.7 –) 1.8–2.5 (– 2.8) (mean ± SD = 2.2 ± 0.2, n = 150).

Distribution.

Japan.

Additional specimens examined.

JAPAN • Aomori: Aomori, Komagome, Fukazawa, Tsukimino Forest Park, dead twigs of T. japonica or T. maximowicziana Shiraz., 14 Oct 2023, R. Yoshioka, Y. Kudo & K. Tanaka, RY 69 (paratype HHUF 30705, culture RY 69); ibid., RY 71 (paratype HHUF 30706, culture RY 71); ibid., RY 73 (paratype HHUF 30707, culture RY 73); ibid., dead twigs of T. japonica or T. maximowicziana, 9 Sep 2024, R. Yoshioka & Y. Kudo, RY 152 (paratype HHUF 30711, culture RY 152); ibid., RY 153 (paratype HHUF 30712, culture RY 153); ibid., RY 161 (paratype HHUF 30713, culture RY 161); Ibaraki: Tsukuba, Kannondai, Forest Research and Management Organization, Arboretum 2, dead twigs of T. japonica, 27 Mar 2024, R. Yoshioka, Y. Kudo & K. Tanaka, RY 92 (paratype HHUF 30709, culture RY 92); Tsukuba, Matsunosato, Forest Research and Management Organization, Arboretum 1, dead twigs of T. kiusiana, 27 Mar 2024, R. Yoshioka, Y. Kudo & K. Tanaka, RY 112 (paratype HHUF 30710, culture RY 112).

Notes.

Splanchospora fulviconidia differs from all other Splanchospora species in having yellowish-brown conidia. Moreover, the conidia [29.5–37 (– 38.5) × 15–19 μm] are the largest amongst the six Splanchospora species examined. The position of the primary septum in the ascospores (mean 0.59) is more central than that of the other Splanchospora species (mean ≥ 0.63).