Therrya pinicola Lan Zhuo & C. L. Hou, 2025

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 pinicola Lan Zhuo & C. L. Hou nom. nov.

Figs 32 , 33

Replacing.

Parvacoccum pini R. S. Hunt & A. Funk , Mycotaxon 33: 52. 1988. To avoid a homonym with Therrya pini (Alb. & Schwein.) Höhn.

Type.

CANADA, B. C., Mesachie Lake , on branches of Pinus monticola Douglas ex D. Don ( Pinaceae ) killed by blister rust, 20 Jun. 1986, R. S. Hunt, DAVFP 23420 (holotype) .

Notes.

Hunt and Funk (1988) described Parvacoccum pini on branches of Pinus monticola in the genus Parvacoccum R. S. Hunt & A. Funk. In the phylogenetic tree, the molecular sequences of Th. strobi form a sister clade to Parvacoccum pini . Parvacoccum pini differs from Th. strobi by having a dark zone below the subhymenium and asci with obtuse apices. Hunt and Funk (1988) established the genus Parvacoccum based on the symmetrically fusiform shape of the ascospores with funnel-shaped appendages, separating it from the genus Coccomyces . However, the fusiform ascospores and the apically expanded paraphyses suggest that the species be placed in Therrya . Given that a species named Therrya pini (Alb. & Schwein.) Höhn. already exists within the genus Therrya , the Therrya pini (R. S. Hunt & A. Funk) L. Zhuo & C. L. Hou would be a later homonym of the former. In accordance with the International Code of Nomenclature for algae, fungi, and plants, we avoid a nomenclatural conflict by selecting “ pinicola ” as the new epithet for the species previously known as Parvacoccum pini .

Therrya pinicola differs from Therrya pini by distinct molecular sequence data and morphologically by short, aseptate ascospores.

This is the first record of Therrya pinicola for China and on the new host Pinus pumila (Pall.) Regel.

Specimens examined.

CHINA, Heilongjiang Province, Yichun, Xing’anling Arboretum , 47.7474°N, 128.8899°E, alt. ca. 300 m, on twigs of Pinus pumila ( Pinaceae ), 16 Jun. 2024, C. L. Hou, L. Zhuo, and Y. Gao, HOU 2237 ( BJTC 2024097 ) ; 47.7474°N, 128.8899°E, alt. ca. 300 m, on twigs of Pi. pumila , 16 Jun. 2024, C. L. Hou, L. Zhuo, and Y. Gao, HOU 2238 B ( BJTC 2024098 ) .

Figures

Figure 32. Therrya pinicola (HOU 2237 / BJTC 2024097) a ascomata on a twig of Pinus pumila b, c mature ascomata. Scale bars: 1 mm (a); 500 μm (b); 1 mm (c).

Figure 33. Therrya pinicola on Pinus pumila (HOU 2237 / BJTC 2024097) a part of an ascoma in vertical section b paraphyses, mature asci with ascospores, and immature ascus c liberated ascospores. Scale bars: 100 μm (a); 10 μm (b); 5 μm (c).