Rubus dianchuanensis Huan C. Wang & Q. P. Wang, 2022

Wang, Qiu-Ping, Li, Yu-Ran, Huang, Qiang-Chun & Wang, Huan-Chong, 2022, Rubus dianchuanensis sp. nov. (Rosaceae) from Sichuan and Yunnan, southwest China, PhytoKeys 193, pp. 141-150 : 141

Rubus dianchuanensis Huan C. Wang & Q. P. Wang sp. nov.

Figs 1 , 2 , 3A1-A5

Type.

China. Sichuan Province: Liangshan Prefecture, Muli County, on the way from Wujiao to Yiji , 27°58'21.73"N, 100°41'51.20"E, 3300-3500 m a.s.l., 23 July 2021, Q. P. Wang et al. ML12992 (holotype YUKU!, isotypes YUKU!) .

Rubus vicarius Focke in Sargent, Pl. Wils. 1: 56. 1911, nom. illeg., non Sudre (1902: 12). Type: China. Sichuan Province , Leshan City, Wa Shan, in thickets, 1500-2100 m a.s.l., July to August 1908, E. H. Wilson 948 (BM!, NYBG!, US!) .

Diagnosis.

Rubus dianchuanensis is most similar to R. ovatisepalus Huan C. Wang, but clearly differs from the latter by its leaf abaxially densely white or grey tomentose, bracts in the inflorescence often leaf-like, pedicels 1-6 cm long, sepals triangular-ovate and with acute to caudate apex.

Description.

Arching shrubs, 1 to 2 m high, deciduous or semi-evergreen. Stems with dense ferruginous glandular hairs and soft eglandular hairs. Branchlets cylindric, grey-green to brown, villous, with curved prickles and nearly straight, ferruginous, 1-2 mm long, glandular hairs. Leaves imparipinnate, usually 3-foliolate, rarely 5-foliolate. Stipules persistent, linear, 5-8 mm long, ca. 1.5 mm wide, pubescent, with glandular hairs, base shortly adnate to petioles. Petioles 0.5-4 cm long, petiolule of terminal leaflets 1-3.5 cm long, lateral leaflets sessile or subsessile; petiolule and rachis with glandular hairs, intermixed pubescence and erect or recurved prickles. Leaf blades cordate or ovate-cordate in outline, papery, adaxially pubescent and with sparse glandular hairs, abaxially densely white or grey tomentose throughout, with sparse glandular hairs along veins. Terminal leaflets cordate, broadly ovate or ovate, 3-11 cm long, 2-7 cm wide, apex acute to acuminate, base rounded to subcordate; margin slightly lobed or not, double serrate; nervation pinnate, with 6-9 lateral veins on each side of the midrib. Lateral leaflets ovate or elliptic, apex acute, base cuneate to round, slightly oblique, 1.5-7 cm long, 1-5 cm wide, lateral veins 5-7 paired. Terminal inflorescences racemose-cymose, 4-10-flowered, 5-15 cm long; bracts at the base usually leaf-like, simple, ovate, ovate-lanceolate or lanceolate, with similar indumentum as the leaves, 2.5-11 cm long, 1-5 cm wide, apex acute to acuminate, base rounded to subcordate; bracts at the upper portion linear, 4-12 mm long, ca. 1 mm wide, pubescent, with glandular hairs. Axillary flowers usually solitary, rarely 2-3-flowered. Pedicels 1-6 cm in length, densely pilose, with dense glandular hairs and curved prickles. Flowers 1-1.5 cm in diameter. Calyx grey-green or reddish, abaxially with soft hairs and glandular hairs; sepals triangular-ovate, erect or spreading after anthesis, 5-10 mm long, 2-4 mm wide, margin grey tomentose and entire, apex acute to caudate. Petals pink to white, obovate, 5-8 mm long, 4-5 mm broad, apex repand, base shortly clawed. Stamens numerous in 2 whorls; filaments linear, glabrous, ca. 5 mm long. Pistils numerous; ovaries sparely pilose, styles glabrous. Aggregate fruit ovoid, orange-red to red.

Taxonomic notes.

Rubus dianchuanensis was firstly collected by Ernest Henry Wilson in 1908 from Wa Shan (Leshan City) in western Sichuan, southwest China. Based on Wilson’s collection, Focke (1911) published " R. vicarius n. form. (?)" with a Latin description in his monograph Species Ruborum . However, the name R. vicarius Focke was not validly published there under Article 36.1 of the Shenzhen Code ( Turland et al. 2018). Shortly afterwards, in July 1911, the name R. vicarius Focke was definitely accepted by Focke (in Sargent 1911) and accompanied by a complete and direct reference, namely "Bibl. Bot. LXXII 211 (Spec. Rub.) (1911)", to his previous Latin description, it was therefore validated. Unfortunately, the name R. vicarius had been previously used by Sudre (1902) for a European species; thus, Focke’s name as a later homonym was illegitimate (Article 53.1 of the Shenzhen Code).

Morphologically, Rubus dianchuanensis is most similar to R. ovatisepalus Huan C. Wang (Fig. 4 ), a species described recently from northwestern Yunnan and southeastern Xizang, southwest China ( Wang and Wang 2019), in having dense glandular hairs throughout the plant and the racemose-cymose terminal inflorescences. However, R. dianchuanensis differs markedly from the latter by its leaf abaxially densely white or grey tomentose (vs. sparsely pubescent, with glandular hairs), bracts at base of the inflorescence usually leaf-like, ovate, ovate-lanceolate or lanceolate (vs. lanceolate to linear), 2.5-11 × 1-5 cm (vs. 0.7-1.2 × 0.1-0.2 cm), flower usually larger, 1-1.5 cm (vs. 0.8-1.2 cm) in diameter, pedicels 1-6 cm (vs. 0.7-1.5 cm) long, apex of sepals acute to caudate (vs. long acuminate to caudate).

Rubus dianchuanensis is also similar to R. subornatus Focke (including its variety R. subornatus var. melanodenus Focke) (Fig. 3B1-B5 ), with which R. vicarius Focke had been erroneously synonymized by Yu and Lu (1985) as well as Lu and Boufford (2003). Nevertheless, R. dianchuanensis differs from it by its not glaucous stems usually covered with dense ferruginous glandular hairs and soft eglandular hairs (vs. more or less glaucous, glabrous), terminal inflorescences racemose-cymose (vs. corymbose), bracts at base of the inflorescence often leaf-like, rarely trifoliolate, ovate, ovate-lanceolate or lanceolate (vs. linear) (Fig. 3 : A3, B3), pedicels usually longer, 1-6 cm (vs. 1-2.5 cm) long, calyx abaxially with grey pubescent (vs. intermixed tomentose) and dense ferruginous glandular hairs (vs. spare or not), without needle-like prickles (vs. with needle-like prickles), and slightly pink to white (vs. purplish-red) petals. Some specimens of R. dianchuanensis had been identified as R. phoenicolasius Maxim., but it is well differentiated from the latter by stems and branches with short glandular hairs (vs. long glandular hairs) and without bristles (vs. dense bristles), terminal inflorescence racemose-cymose (vs. short racemes) 5-15 cm (vs. 1-6 cm) long, pedicels 1-6 cm (vs. 0.5-1.5 cm) long, flowers 1-1.5 cm (vs. 0.6-1.5 cm) in diameter, calyx without bristles (vs. with dense bristles), sepals triangular-ovate (vs. lanceolate). A detailed morphological comparison between these four species is summarized in Table 1 .

Phenology.

Rubus dianchuanensis flowering from June to August, fruiting from July to September.

Etymology.

The specific epithet “dianchuanensis” refers to the Yunnan (called dian for short in Chinese) and Sichuan (called chuan for short in Chinese) provinces, where this species occurs.

Distribution and habitat.

Rubus dianchuanensis is endemic to southwest China, where it has been collected from western Sichuan and northwestern Yunnan (Fig. 5 ). It usually occurs at elevations ranging from 2500-3600 meters and grows in open woods and thickets.

Additional specimens examined

(Paratypes): China. Sichuan: Muli County, Damadian, 3000 m a.s.l., 16 Aug 1937, T. T. Yu 7740 (PE); Shimian County , Liziping Country, 2700 m a.s.l., 28 Jul 1978, Shimian Team 78-0875 (SM); Shimian County , 1955, C. C. Hsieh 41198 (IBSC, PE); Kangding City, Zheduotang village , 3100 m a.s.l., 1 Aug 1963, K. C. Kuan et all 1218 (PE); same location, 3450 m a.s.l., 5 July 1953, X. L. Jiang 36185 (IBK, IBSC, PE); same location, 3600 m a.s.l., 16 Jul 1953, W. P. Fang & X. L. Jiang 36323 (IBK, ISBC, PE); Kangding County , 2750 m a.s.l., 24 Jun 1980, Z. J. Zhao 112962 (CDBI) and Z. J. Zhao 119262 (PE); Kangding City, Yajiageng, Laoyunshachang, 3318 m a.s.l., 101°58'17"E, 29°56'00"N, 28 Aug 2008, Y. L. Peng & W. G. Tu Gaoxf-0856 (KUN); Xiaojin County , 3500 m a.s.l., 1 Jul 1959, Z. G. Liu 0412 (CDBI, PE); Lixian County , 26 Aug 1957, X. Li 74160 (IBSC, PE, NAS); Lixian County , Miyaluo village , 25 Jul 1958, Z. L. Wu 33375 (PE; CAF); Barkam City, Barkam County , Dalangjiao River , 2300-2900 m a.s.l., 12 Jul 1960, Sichuan Medicine Source Survey Team 22297 (NAS, SM); Barkam City, 2800 m a.s.l., 11 Jul 1957, H. F. Zhou & Z. Y. Zhang 22772 (IBSC, NAS, KUN, PE); Barkam City, Dalangzugou, 2700 m a.s.l., 27 Aug 1957, X. Li 72288 (IBSC, NAS, PE); Heishui County , Naizigou, 2900 m a.s.l., 22 Jul 1957, X. Li 73260 (IBSC, NAS, KUN; PE) . Yunnan: Ninglang County, Lugu Lake , 27°39'21"N, 100°48'36"E, 2500-2600 m a.s.l., 6 Aug 2015, H. C. Wang et al. LGH8164 (YUKU) .

Figures

Figure 1. Rubus dianchuanensis A habit B bract at the base of inflorescence C bract at the upper part of inflorescence D calyx E flower (side view) F aggregate fruit with persistent calyx.

Figure 2. Rubus dianchuanensis A, B habit C abaxial surfaces of leaves D portion of branchlet showing glandular hairs E flower F an immature aggregate fruit with calyx.

Figure 3. Rubus dianchuanensis (A 1 - A 5) and R. subornatus (B 1 - B 5) A 1 a flowering branch showing terminal inflorescence A 2 portion of stem showing indumentum A 3 bract at the base of inflorescence A 4 flower (side view) A 5 mature aggregate fruit B 1 habit B 2 portion of the stem B 3 bracts B 4 flower (side view) B 5 mature aggregate fruit.

Figure 4. Rubus ovatisepalus A habit B abaxial surfaces of leaflets C mature aggregate fruit.

Figure 5. Geographical distribution of Rubus dianchuanensis (red dots).