Therrya Sacc.

Zhuo, Lan, Wang, Hai-Qi, Zhang, Peng, Sui, Xiao-Nan, Guo, Mei-Jun, Wang, Shi-Juan & Hou, Cheng-Lin, 2025, New genera and species of coniferous twig-inhabiting Rhytismatales from China, IMA Fungus 16, pp. e 138790-e 138790 : e138790-

Therrya Sacc. , Michelia 2 (no. 8): 604. 1882.

Type.

Therrya pini (Alb. & Schwein.) Höhn. , Ber. dt. bot. Ges. 35: 422. 1917.

Sexual morph.

Ascomata scattered to clustered, circular to slightly irregular, sessile, dark brown to black, opening by irregular splits. Covering stroma formed by dark brown (# 2 b 180 b) to black (# 000000), thick-walled angular cells. Epithecium present or absent. Basal Covering stroma poorly or well developed, consisting of carbonized, thick-walled, angular cells. Internal matrix of Covering stroma well developed, formed by thin-walled, irregular cells or hyaline hyphae, filled or not filled with crystals. Subhymenium consisting of textura intricata or hyaline cells. Paraphyses filiform, not branched, tips swollen or not swollen. Asci ripening sequentially, clavate, thin-walled, J –, 8 - spored or 4 - spored. Ascospores aseptate to septate, filiform or fusiform, hyaline, covered or not covered by a gelatinous sheath.

Asexual morph.

Conidiomata scattered or gregarious, lenticular, 300–500 μm in diam, dark brown to black, ostiole absent, opening by irregular tears in thecovering layer. In vertical section, conidiomata subepidermal, upper layer and basal layer 20–60 μm thick, consisting of pale to dark brown textura angularis, with thin- to thick-walled cells. Conidiogenous cells smooth, cylindrical to ampuliform, discrete, holoblastic, sympodial to synchronous, 9–11.5 (– 13) × 2–2.5 μm. Conidia aseptate, hyaline, smooth, cylindrical, straight to curved, with rounded apices, 8–12 (– 22) × 1–1.5 (– 2) μm (Description based on Reid and Cain 1960; McMullin et al. 2019).

Notes.

Reid and Cain ( 1960) reviewed the taxonomic history of the genus Therrya , listing numerous synonyms under three species names: Coccomyces strobi , Therrya fuckelii (Rehm) Kujala , and Therrya pini . Korf (1973) accepted this treatment and emphasize fusiform, multiseptate ascospores lacking gelatinous sheaths as key diagnostic features. Sherwood (1980) further delineated the genus by highlighting its substrate specificity — epiphytic on coniferous substrates — and the epithecium of inflated paraphyses cemented in a brown gel. According to Index Fungorum (https://www.indexfungorum.org) records, there are currently seven legitimate names for the genus Therrya , which are Th. abieticola C. L. Hou & M. Piepenbr. , Th. eucalypti Z. Q. Yuan , Th. fuckelii , Th. piceae A. Funk , Th. pini , Th. pseudotsugae , and Th. tsugae A. Funk. Based on Hou and Piepenbring (2007), Th. eucalypti Z. Q. Yuan might be closely related to Colpoma Wallr. instead of Therrya based on its morphology and host. Therrya abieticola , originally placed within this genus, has been transferred to the genus Neotherrya in the present study. Molecular data are available for only two species, Th. fuckelii and Th. pini . Phylogenetic analysis reveals a distinct clade comprising Co. guizhouensis , Co. strobi , Parvacoccum pini , Th. fuckelii , and Th. pini (Clade 4, Fig. 1 ), exhibiting morphological similarities with other members of the genus. Based on phylogenetic inference and morphological affinities, it is proposed to transfer Co. strobi , Co. guizhouensis , and Pa. pini into the genus Therrya .

Figures

Figure 1. Phylogenetic tree derived from maximum likelihood analysis of combined ITS, nrLSU, and mtSSU rDNA sequences of Rhytismatales, using Cudoniella clavus (AFTOL-ID 166) and Pezicula carpinea (KUS-F 51029) as outgroups. Bootstrap support values for ML analysis (MLB) and MP analysis (MPB) greater than 70 % and Bayesian posterior probabilities (PP) greater than 0.95 are given above the nodes. Names of new species and a new combination are written in bold. Species name T – Type species; Species name H – Holotype.