Chrysomyxa zhuoniensis C. J. You & J. Cao, 2017

Cao, Jing, Tian, Cheng-Ming, Liang, Ying-Mei & You, Chong-Juan, 2017, Two new Chrysomyxa rust species on the endemic plant, Picea asperata in western China, and expanded description of C. succinea, Phytotaxa 292 (3), pp. 218-230 : 224

Chrysomyxa zhuoniensis C. J. You & J. Cao , sp. nov. ( Fig. 2 )

MycoBank no.:—MB819570

Etymology:— zhuoniensis , referring to the location of the type specimen.

Diagnosis:— Chrysomyxa zhuonisis differs from all other Chrysomyxa species on Picea in possessing aeciospores with a distinct broad longitudinal smooth cap at ends of spores.

Type:— CHINA, Gansu Province: Zhuoni County, on Picea asperata Mast. ( Pinaceae ), 7 August 2012, coll. Y.M. Liang &T. Yang (Holotype: BJFC-R00521). Gansu Province: Zhuoni County, on Picea asperata Mast. ( Pinaceae ), 7 August 2012, coll. Y.M. Liang & T. Yang (Paratype: BJFC-R00522).

Spermogonia, uredinia and telia unknown.

Aecia discrete, not confluent, tongue-like, even in width, 0.2–0.5 mm, up to 3 mm long, mostly epiphyllous ( Fig. 2A ). Aeciospores ellipsoidal, or ovoid, 24–37 × 17–28 μm, wall plus warts 1.9–3.4 μm ( Fig. 2B ), with a distinct broad, shallow, and smooth cap at one or both ends, with a broken, fissured edge, warts crowded, annulate, tapered or irregular in shape, 4–6 annuli, with uneven tops ( Figs 2C, 2D, 2E ); aecial peridium persistent, cells polygonal, round or square, outer surface deeply convave, with sharply defined edges, slightly rough surface, inner surface flat to convex, with raised edges, warts distinct and densely crowded ( Figs 2F, 2G ).

Notes:—There are two Chrysomyxa species, C. nagodhii and C. cassandrae in North America, that resemble C. zhuoniensis ( Table 3). They both have aeciospores with a conspicuous longitudinal cap, but differ in the surface appearance of the cap ( Crane 2005b), with C. nagodhii having a rougher cap with a smooth edge than C. zhuoniensis , and C. cassandrae with a more broad shallow warted cap with a broken edge. C. zhuoniensis differs from the other five known Chrysomyxa species occurring on spruce needles in China in its smoother longitudinal cap at ends of aeciospore, with a broken and fissured edge ( Fig 2C, 2D ) ( Table 2). C. ledi psossesses aeciospore with a narrow longitudinal groove, features not seen in C. zhuoniensis . C. qilianensis and C. woroninii which lack a cap on the aeciospore, and the present species C. zhuoniensis , with a conspicuous cap at ends of aeciospore, appears to be distinctly different in aeciospore characters, and C. rhododendri and C. succinea possess aeciospores with a poorly defined longitudinal smooth stipe ( Tai 1979, McBeath 1984, Wang 1987, Cao & Li 1996, 1999, Cao 2000, Crane 2005b, Zhang 2005, Kaitera et.al. 2010).

Figures

FIGURE 2. Chrysomyxa zhuoniensis (BJFC-R00521, holotype).A. Gross features of infected needles. B. Aeciospores observed by LM. C–D. Single aeciospores, showing longitudinal smooth cap with broken, fissured edge. E. Crowded, cylindrical warts with uneven tops. F. Aecial peridium with smooth outer surface. G. Aecial peridium with densely warted inner surface. Scale bars: A = 500um; B = 20 μm; C= 10um; D and E = 5 μm; F and G = 30 μm.