Cronartium peridiatum P. Zhao & L. Cai, sp. nov.,
MycoBank number: MB 842422; Index Fungorum number: IF 842422; Facesoffungi number: FoF 12571;
Spermogonia not found. Aecia peridermioid, intracortical in origin, erumpent, peridia cylindric, 5–12 mm high, peridial cells ellipsoid or oblong, 28–49 × 14–21 µm, outer layers smooth, inner wall rugose, aeciospores borne singly, ellipsoid, obovoid, or subglobose, 14–25 × 11–19 µm, wall 2.0–3.0 µm thick including verrucae connected by filaments, verrucae 1.4–2.5 µm high, densely verrucose, nailhead-like verrucae with 2–4 annuli, with obviously smooth area on surface. Uredinia usually lacked. Telia hypophyllous, hair-like columns, 0.3–1.5 mm long, straight or slight curved, light yellow, cross-section of telia with 7–12 teliospores, teliospores 30–80 × 8–20 µm, oblong, catenulate, wall brown, 0.3–1.6 µm thick, without surface ornamentation.
Material examined: Canada, Ontario, 0, I on P. strobus, May 1952, collector unknown, NYBG267053 (holotype);Bolivia, III on Eupatorium subscandens, 25 May 1920, E.W.D. Holway, MICH278063; Bolivia, III on Eupatorium odoratum, 23 Dec 1927, H. Sydow, MICH278062; Canada, Alberta, III on Ribes sp., 16 Sept 1998, H. Schalkwijk, HMAS86824; Canada, Quebec, III on R. nigrum, F. Godbout, NYBG267052; Quebec, III on Ribes sp., Aug 1950, S.M. Pady, NYBG267061; China, Heilongjiang, III on R. mandschuricum, 28 Aug 1977, L.P. Shao, HMAS38589; China, Xinjiang, III on Ribes sp., data unknown, Z.K. Liu, HMAS37742; USA, New York, III on R. nigrum, 18 Aug 1932, W.L.C. Muenscher, NYBG267051; USA, New York, III on Ribes sp., 31 Jul 1951, S.M. Pady, NYBG267057.
Distribution: China, Canada, Bolivia.
Sequence data: SSU: OM746014; ITS: MK208298; LSU: MK193829; CO3: OM721437 (holotype).
Notes: In the phylogenetic tree, C. peridiatum was allied to C. ribicola. Morphologically, it differs from C. ribicola in the dimension of aeciospores (14–25 × 11–19 µm vs 22–38 × 16–27 µm). In addition, peridial cells in C. peridiatum have rugose inner wall, whereas those in C. ribicola have 3–5 annuli. Aecial stage of C. peridiatum is found on P. strobus, while telial stage is found on Eupatorium odoratum, R. nigrum, R. mandschuricum and Pedicularis sp.. Previously, C. sahoanum, C. yamabense, and C. ribicola were reported on P. strobus, but they differ from C. peridiatum in the morphology of teliospores, shape of verrucae on aeciospores and peridial cells (Hiratsuka et al. 1992). Cronartium andinum, C. eupatorinum, and C. praelongum, have been found on Eupatorium odoratum (Sydow & Sydow 1915), but C. peridiatum differs from these species in the dimension of teliospores (30–80 × 8–20 µm vs 70–100 × 11–14 µm, 28–44 × 13–20 µm, 12–15 × 8–10 µm).
Fig. 5. Cronartium peridiatum (holotype). a. Label of holotype specimen; b. Peridermioid aecia on P. strobus; c. Ellipsoid, obovoid, or subglobose aeciospore observed by SEM; d. Nailhead-like verrucae on aeciospore; e. Ellipsoid or oblong peridial cells observed by SEM; f. Rugose surface of peridial cells inner wall; g. Uredinia and telia on R. nigrum; h. Hair-like telia; i. Telia observed by SEM; j. Urediniospore observed by SEM; k. Section of a telium observed by LM; l. Telium with ostiolar cells observed by SEM. Scale bars: c = 10 µm; d–f = 20 µm; i = 200 µm; j = 5 µm; k–l = 50 µm.