Cronartium ribis-taedae P. Zhao & L. Cai, sp. nov.,
MycoBank number: MB 842424; Index Fungorum number: IF 842424; Facesoffungi number: FoF 12573;
Spermogonia not found. Aecia light brown, hypophyllous, 0.2–0.6 mm, becoming erumpent, aeciospores borne singly, ellipsoid, obovoid, or subglobose, 16–33 × 12–21 µm, wall 2.0–3.0 µm thick, verrucae connected by filaments, verrucae 1.4–2.5 µm, densely verrucose, nailhead-like verrucae with 3–5 annuli, with obviously smooth area on surface. Uredinia usually lacked, urediniospores occasionally accompanying with telia, echinulate, sometimes with smooth surface at apex. Telia hypophyllous, hair-like columns, 0.4–1.5 µm long, straight or slight curved, light yellow, cross-section of telia with 4–10 teliospores, teliospores oblong, 40–58 × 8–15 µm, catenulate, wall yellowish brownish, 0.5–1.3 µm thick, without surface ornamentation.
Material examined: China, Florida, 0, I on P. taeda, 27 Feb. 1919, G.G. Hedgcock, FLAS-F-16581 (holotype); China, Xinjiang, III on R. nigrum, 5 Sept 2004, J.Y. Zhuang, HMAS172046; Xinjiang, III on Ribes sp., 16 Aug 1986, J.Y. Zhuang, HMAS52871; USA, Florida, 0, I on P. taeda, 29 Mar. 1928, A.N. Tissot, FLAS-F-7199; Florida, 0, I on P. taeda, 29 Mar. 1928, A.N. Tissot, FLAS-F-7200; Florida, 0, I on P. caramels, 6 Mar. 1918, G.G. Hedgcock, FLAS-F-16562; North Carolina, 0, I on P. echinata, 30 Apr 1916, G.G. Hedgcock, FLAS-F-16567; South Carolina, III on Ribes sp., 19 Apr 1916, G.G. Hedgcock, FLAS-F-16578.
Sequence data: SSU: OM746014; ITS: MK208298; LSU: MK193829; CO3: OM721437.
Notes: In the phylogenetic tree, C. ribis-taedae is phylogenetically sister to C. ribicola and C. peridiatum, but differs from these two allied species in ornamentation of aeciospores and the dimension of teliospores. Host alternation of C. ribis-taedae was found between P. taeda and R. nigrum.
Fig. 7. Cronartium ribis-taedae (holotype). a. Aecia on stem and needle of P. taeda; b. Ellipsoid, obovoid, or subglobose aeciospores observed by SEM; c. Nailhead-like verrucae on aeciospores; d. Hair-like telia; e. Telia observed by SEM; f. Teliospores with smooth surface. Scale bars: b = 10 µm; c = 2 µm; d = 500 µm; e = 100 µm; f = 50 µm.