Phragmidium longissima Y. M. Liang & T. Yang, 2015

Yang, Ting, Chang, Wei, Cao, Bin, Tian, Cheng-Ming, Zhao, Long & Liang, Ying-Mei, 2015, Two new Phragmidium species identified on Rosa plants native to China, Phytotaxa 217 (2), pp. 182-190 : 186-187

publication ID	https://doi.org/ 10.11646/phytotaxa.217.2.8
persistent identifier	https://treatment.plazi.org/id/038E87AF-FFA5-7C45-FF5F-0CC02FF6FDB6
treatment provided by	Felipe
scientific name	Phragmidium longissima Y. M. Liang & T. Yang
status	sp. nov.

Treatment

Phragmidium longissima Y. M. Liang & T. Yang , sp. nov. ( Fig. 2 View FIGURE 2 )

MycoBank no.:—MB811452

Etymology:— Longissima , referring to the characteristically long teliospores of this species.

Diagnosis:—Urediniospores uniformly echinulate, with pore membrane at the germ pore, telia black, teliospores (8–)9–11(–12)-celled, 85–122 × 21–30 μm, wall dark brown, verrucose, papilla 2.5–5.5 μm, verrucose, pedicel length 0.5−1 times the spore length.

Holotype:— CHINA, Yunnan Province, Lanping County, Mt. Changyan , on Rosa lichiangensis T. T. Yu & T. C. Ku , 18 September 2011, coll. T. Yang, Exsiccate BJFC-R00338 .

Paratype:— CHINA, Yunnan Province, Lanping County, Mt. Luoguqing, on Rosa lichiangensis T. T. Yu & T. C. Ku , 19 September 2011, coll. T. Yang, Exsiccate BJFC-R00360.

Spermogonia and aecia unknown.

Uredinia hypophyllous, scattered or loosely grouped, minute, rounded, 0.05–0.2 mm across, pale yellow; paraphyses numerous, clavate or broadly clavate, 42–75 × 16–30 μm, sub-erect or incurved, located around the sorus, wall smooth, colourless ( Fig. 2A View FIGURE 2 ); urediniospores globose or sub-globose, 20–26 × 18–21 μm, wall approximately 1 μm thick, uniformly echinulate, colourless, wall at germ pore conspicuously intruding in the spore lumen to form a pore membrane ( Figs 2B, 2C View FIGURE 2 ). Telia produced on the abaxial leaf, scattered or grouped, minute, irregular in shape, 0.1– 0.3 mm across, early naked, pulverulent, black ( Fig. 2E View FIGURE 2 ); teliospores cylindrical, 8–12-celled, generally 9–11-celled, 85–122 × 21–30 μm, round at both ends, not constricted at the septum, apical papillae obtuse, approximately 2.5–5.5 μm long, brownish-yellow, densely verrucose, usually two germ pores in each cell, wall approximately 2–5 μm thick, dark brown, densely and minutely verrucose, with colourless tubercles ( Figs 2D, 2F–2I View FIGURE 2 ); pedicles persistent, 65–111 μm long, average length 0.5−1 times the spore length, swelling broadly clavate at the lower half, approximately 11–17 μm at the broadest diameter, brownish-yellow in the upper half, nearly colourless in the lower half, smooth ( Figs 2C, 2H View FIGURE 2 ).

Notes:— Phragmidium longissima differed from Ph. rosae-multiflorae in that it had uniformly echinulate urediniospores ( Fig. 2B View FIGURE 2 ) and generally 9–11-celled teliospores ( Figs 2D, 2F View FIGURE 2 ), whereas the latter was characterized by verrucose urediniospores and mostly 7–8-celled teliospores. Phragmidium . rosae-multiflorae pedicels were obviously wider (up to 30 μm) than those of Ph. longissima ( Wei 1988, Hiratsuka et al. 1992, Zhuang et al. 2012). Phragmidium americanum was similar to Ph. longissima with respect to teliospore size and cell number, but was distinct in that teliospores were sometimes slightly narrowed above and the pedicel length averaged 1−1.5 times the spore length ( Cummins 1931, Wahyuno 2001). Phragmidium longissima resembled Ph. rosae-californicae in the size of teliospores and pedicels, but was distinguished by the rounded cells at both teliospore ends ( Fig. 2D View FIGURE 2 ). Phragmidium rosae-californicae was characterized by teliospores strikingly acuminate above and with a typically longer apical cell, which graded directly into the apiculus ( Cummins 1931). Phragmidium americanum and Ph. rosae-californicae are distributed primarily in North America and have never been recorded in China ( Cummins 1931). Phragmidium longissima was the first Phragmidium species reported on Rosa lichiangensis , which obviously differed from all the previously described Phragmidium species by the uredinial and telial host range ( Wei 1988, Hiratsuka et al. 1992, Wahyuno 2001, Tykhonenko 2007, Zhuang & Wei 2009, Zhuang et al. 2012).