Cronartium murrayanae P. Zhao, X. Qi, & L. Cai, sp. nov.,

MycoBank number: MB 842420; Index Fungorum number: IF 842420; Facesoffungi number: FoF 12569;


Spermogonia not found. Aecia hypophyllous, light brown, 0.2–0.6 mm, becoming erumpent, peridial cells globose or ellipsoid, 18–26 × 13–17 µm, cell walls about 2–4 µm thick, outer walls smooth, inner walls verrucose, warts annulate, 2–3 annuli, aeciospores borne singly, ellipsoid, obovoid, or subglobose, 29–62 × 11–22 µm, wall hyaline, with apparent tips at apex, 2.0–3.0 µm thick including verrucae connected by filaments, densely verrucose, warts annulate, 1–2 annuli, with obviously smooth area on surface, contents yellow. Uredinia and telia not found.

Material examined: USA, Wyoming, III on P. murrayana, 24 Jul 1922, L.E. Wehmeyer, MICH301494 (holotype); Canada, Alberta, 0, I on P. murrayana, 5 Jul 1907, E.W.D. Holway, FLAS-F-4906; USA, Colorado, 0, I on P. murrayana, 15 Aug 1906, Bartholomew, FLAS-F-4907; USA, Wyoming, 0, I on P. murrayana, 24 Jul 1922, L.E. Wehmeyer, MICH301496.

Distribution: Canada, USA

Sequence data: SSU: OM745993; ITS: OM746425; LSU: OM746590; CO3: OM721416 (holotype).

Notes: In the phylogenetic tree, C. murrayanae is phylogenetically close to C. comandrae and C. pyriforme. Morphologically, it differs from these two species in the dimension and shape of peridial cells, and a detailed morphological comparison was provided in the notes to C. comandrae. Previously, C. coleosporioides, C. comptoniae and C. harknessii have been reported on P. murrayana (Farr & Rossman 2019), but these species are phylogenetically distinct and morphologically distinguishable from C. murrayanae.

Fig. 3. Cronartium murrayanae (holotype). a. Aecia on P. murrayana; b. Ellipsoid or globose peridial cells observed by SEM; c. Ornamentation of peridial cells observed by SEM; d. Ellipsoid or obovoid aeciospore observed by SEM. Scale bars: b = 20 µm; c = 5 µm; d = 20 µm.