Phragmidium coreanicola Q. F. Zhang, Q. Z. Wu & Q. R. Li, 2025

Phragmidium coreanicola Q. F. Zhang, Q. Z. Wu & Q. R. Li sp. nov.

Fig. 3 View Figure 3

Type.

China • Guizhou Province, Guiyang City, Campus of Guizhou Medical University (26°22'48"N, 106°37'30"E), 1911 m a. s. l., on leaves of Rubus coreanus ( Rosaceae ), 7 October 2021, Q. Z. Wu (holotype GMB 0101 , isotype KUN-HKAS 144249 ) GoogleMaps .

Etymology.

The epithet refers to the host species, Rubus coreanus Miq. var. coreanus , from which the holotype was collected.

Description.

Spermogonia and Aecia not found. Uredinia 0.1–0.7 mm diam., produced on the abaxial leaf surface, scattered to gregarious, hypophyllous, yellow spots, scattered, irregular patches. Urediniospores 20–29 × 14–25 μm (av. = 24 × 21 μm, n = 30), globose to subglobose or broadly elliptical to ellipsoidal, wall 0.8–2.1 μm thick (av. = 1.4 μm, n = 30), inconspicuous or smooth at the base; inclusions orange-yellow or pale-yellow; germ pores 2–3, sub-equatorial. Telia 0.1–0.9 mm diam., hypophyllous, dark brown to black, clustered or scattered, bacilliform. Teliospores 107–167 × 25–35 μm (av. = 134 × 30 μm, n = 30), cylindrical, 5–7 cells, often 6, reddish-brown to opaque, rounded at the apex, rounded or somewhat attenuate at the base, not or slightly constricted at the septum, pedicels sub-hyaline, persistent, 47–96 × 12–19 μm (av. = 68 × 16 μm, n = 30), with a swollen base that gradually shows orange-yellow contents towards the lower end. Pedicel broken; paraphyses not seen.

Additional material examined.

China • Guizhou Province, Qingzhen City (26°34'58"N, 106°28'28"E), 1972 m a. s. l., on leaves of Rubus coreanus ( Rosaceae ), 7 October 2021, Q. Z. Wu ( GMB 4071 ) GoogleMaps .

Notes.

Phragmidium coreanicola formed a separate branch in our phylogenetic analyses (Fig. 1 View Figure 1 ). Morphologically, P. coreanicola differs from P. griseum in having slightly wider urediniospores (14–25 μm vs. 13–21 μm) and larger teliospores (107–167 × 25–35 μm vs. 50–125 × 18–28 μm) ( Liu et al. 2018). Additionally, P. coreanicola is reported on Rubus coreanus , whereas P. griseum was found on Rubus crataegifolius . Phragmidium coreanicola differs from P. cibanum , which is reported on Rubus niveus , by having bigger urediniospores (20–29 × 14–25 μm vs. 17–20 × 18–19 μm) and larger teliospores (107–167 × 25–35 μm vs. 80–100 × 20–30 μm) ( Wei 1988; Hiratsuka et al. 1992; Liu et al. 2018). Phragmidium coreanicola has the same host species as P. rubi-coreani in Guiyang City. However, P. coreanicola has larger teliospores (107–167 × 25–35 μm vs. 29–74 × 14–37 µm) ( Sun et al. 2022). The morphological comparison between P. coreanicola and P. pauciloculare shows that the uredinia of P. coreanicola are larger than those of P. pauciloculare (0.1–0.7 mm diam vs. 0.2–0.3 mm diam), and teliospores of P. coreanicola are also larger than those of P. pauciloculare (107–167 × 25–35 μm vs. 35–111 × 18–27 µm) ( Wei 1988).

Furthermore, the ITS sequences of P. coreanicola and P. griseum exhibit significant differences, with a similarity of 87.33 %. However, the LSU sequences of P. coreanicola and P. griseum have little variation, sharing a similarity of 99.38 %.