A New Species and a New Name in Rosa (Rosaceae) from China

Abstract

Rosa alexandrae Buzunova (sect. Synstylae DC.) is described. The new name R. uniflorella is proposed to replace the later homonym R. unifora Yu & Ku. Among the collections made by G. N. Potanin from China and deposited at the Komarov Botanical Institute (LE), there is an undescribed species of Rosa. It is named here for his wife, A. V. Potanina, who accompanied him during his expedition to China and Mongolia. Rosa alexandrae Buzunova, sp. nov. TYPE: China. Gansu: valley of Pei-schui, near Litschapu, 19 June 1885 (fl), G. N. Potanin s.n. (holotype, LE). Figure 1. Frutex altus; aculei 4-5 mm longi, aduncti. Foliola 35, 2-3(-4) cm longa, 1.5-2 cm lata, elliptica vel obovata, margine simpliciter dentata. Flores albi, 9-11 depositi, 1.5-2 cm in diam., bracteati. Pedicelli 1-1.5 cm longi, glanduloso-setulosi. Sepala integerrima, 6-7 mm longa, ovato-lanceolata, dorso plerumque pilosa et glandulosa. Styli coaliti; columna stylaris 4-5 mm per orificium disci excedens, dense pilosa. Hypanthia globosa vel late ellipsoidea, 3-4 mm in diam., glabra. Fructus ignoti. Tall-growing shrubs with erect or flexuous branches. Cortex reddish. Prickles 4-5 mm long, sparse, + uniform, hooked, with a dilated base. Leaves 6-8 cm long, rachis densely pubescent, glandular, prickly; stipules 8-10 x 1-1.2 mm, entire at margin, with acuminate auricles 2-3 mm long, usually diverging. Leaflets 3-5, 2-3(-4) x 1.5-2 cm, broadly ovate or obovate, glabrous or sparsely pubescent adaxially, densely pubescent and sometimes sparsely glandular abaxially, base rounded to cuneate, margin uniserrate with short and broad teeth, apex obtuse. Corymbs loose, usually 9-11flowered; bracts rather short, entire, pubescent. Flowers white, 1.5-2 cm diam. Pedicels 1-1.5 cm long, glabrous or pubescent, usually glandular-hispidous. Sepals entire, 6-7 mm long, ovate-lanceolate, acuminate, pubescent and glandular on the back. Styles connate in a pubescent column up to 4-5 mm long. Hypanthia globose to ovoid, 3-4 mm diam. Fruit unknown. Rosa alexandrae apparently does not have close relatives among the 18 Chinese species of section Synstylae, especially the three species with 3-5foliolate leaves and entire stipules, with which it should be associated. It is probably remotely related to R. weisiensis Yu & Ku, which is readily distinguished from R. alexandrae by its straight, basally dilated prickles and narrower leaflets. Rosa uniflorella Buzunova, nom. nov. Replaced name: Rosa unifora Yu & Ku, Bull. Bot. Res. North-East. Forest. Inst. 1(4): 12. 1981, not Galushko Bot. Mater. Gerb. Bot. Inst. Komarova Akad. nauk SSSR 19: 204-217. 1959: 212. TYPE: China. Zhejiang: Daishan Xian, L. C. Chiu & R. L. Lu 9605 (holotype, HP). The Chinese Rosa uniflora Yu & Ku is a later homonym of the Caucasian R. uniflora Galushko. Therefore, a new name is proposed for the Chinese plant. Acknowledgments. I am grateful to Ihsan AlShehbaz and James Solomon for their help with the manuscript. NOVON 4: 209-210. 1994. This content downloaded from 157.55.39.138 on Thu, 19 May 2016 05:08:07 UTC All use subject to http://about.jstor.org/terms