Youngia purpimea Y.L. Peng, W.B. Ju, X.F. Gao & Y.D. Gao, 2015

Peng, Yu-Lan, Ju, Wen-Bin, Gao, Xin-Fen & Gao, Yun-Dong, 2015, Youngia purpimea (Asteraceae), a new species from Sichuan, China, Phytotaxa 236 (2), pp. 191-195 : 191-194

Youngia purpimea Y.L. Peng, W.B. Ju, X.F. Gao & Y.D. Gao , sp. nov. ( Figs. 1 & 2 )

Diagnosis:—The new species is most similar to Youngia szechuanica ( Söderberg (1934: 362) Hu (1969: 37) [= Y. scaposa Babcock & Stebbins (1937: 45) , nom. illeg., according to Art. 52.1 of the Melbourne Code (McNeill et al. 2012)], but is distinct by having leathery undivided caudical leaves being glabrous on both surfaces and purplish red abaxially, leaf margins sparsely dentate, and also by brown pappus ( Figs. 1 & 2 ).

Type:— CHINA. Sichuan Province: Xuyong County, Huagaoxi Nature Reserve, Shuiwei Town, Guangmu Village, on the wet rock near waterfall, 650 m, 5 July 2013, Xin-Fen Gao, Yung-Dong Gao & Wen-Bin Ju, HGX11571 (holotype & isotypes, CDBI).

Perennial herb, rhizomatous, height 28–34 cm, with leaves basally crowded on a short apically brown-woolly caudex, stems erect, solitary, almost leafless, smooth and glabrous. Caudical leaves 5–6, lamina narrowly ovate, 2–6 cm wide, 6–16 cm long, margin sparsely and shallowly sinuate-dentate with long-acuminate teeth, apex acuminate, base attenuate into a petiole, 4–15 cm long. Cauline leaves few, supporting the synflorescence branches, linear or bract-like. All leaves thick-textured, mostly leathery, both surfaces glabrous, abaxially purplish red. Capitula numerous, in a paniculiform-corymbiform synflorescence. Capitulum with five flowers. Involucre with phyllaries in 3–4 series, outermost phyllaries 1.5 mm long, 1 mm wide, apex acute; inner phyllaries 7–8 mm long, 1.5 mm wide. Flowers yellow, corolla tube 2 to 3 mm long, pubescent with short hairs, ligule 3–4 mm long, 2 mm wide, anther tube 3 mm long, style branches 1.8–2.8 mm long. Immature achenes yellow brown, ribs unequal, flattened, length 1–2 mm. Pappus 4–5 mm long, brown, 2-seriate.

Etymology: —” Purp-” refers to the abaxially purplish red leaves of the new species; “- imea ” is an artificial ending.

Distribution and habitat:—The new species is known only from the type locality and the adjacent Longfeng

Town in Xuyong County of Sichuan Province, China, at elevations between 500–800 m, growing on wet rock slopes.

Additional material examined (paratype): — CHINA. Sichuan Province. Huagaoxi Nature Reserve, Xuyong County, Longfeng Town, elev. 500 m, 28°15 ′ 06 ″ N, 105°28 ′ 26 ″ E, 9 May 2014, W.B. Ju, L. Zhang, X.M. Zhou, L. Zhang & Y.L. Peng 1601 (CDBI).

Phenology:—Flowering and fruiting from May to July.

Discussion:—Morphologically, Youngia purpimea is most similar to Y. szechuanica in having 5-flowered capitula and few bract-like cauline leaves and brown-woolly short caudex. However, Y. purpimea is different from Y. szechuanica by having leathery undivided caudical leaves with long petioles, leaf margins entire or sparsely dentate, and brown pappus. Youngia purpimea is also close to Y. zhenyiana Deng et al. (2014: 265) in having 5-flowered capitula, but the latter has soft, large, lyrately pinnatisect cauline leaves. Youngia purpimea is unique by having the combination of its mostly leathery leaves, glabrous on both surfaces, purplish red abaxially ( Fig. 2C ), long petioles, and brown-woolly short caudex ( Fig. 2E ), five yellow flowers ( Fig. 1A, B & Fig. 2C ), and brown pappus.

The delimitation of Youngia is sometimes confused with Crepidiastrum Nakai (1920: 140) , Crepis Linnaeus (1753: 805) , Ixeris Nakai (1920: 155) , Faberia Hemsley (1888: 479) , Ixeridium ) Gray 1859: 397) Tzvelev (1964: 388), and Prenanthes Linnaeus (1753: 797) s.l. [incl. Nabalus Cassini (1825: 94) ], because of the reticulate evolution in tribe Cichorieae ( Peng et al. 2014) . We also compared Y. purpimea with the species of those similar genera. This new species looks like Ixeridium laevigatum Blume (1826: 886) Pak & Kawano (1992: 45) at the first glance in having similar leaves and five ray flowers and brown pappus, but this species can be distinguished from Ixeridium by having flat unbeaked achenes, which only appear in Youngia . Leathery purplish red leaves of Y. purpimea are reminiscent of the leaves of Faberia nanchuanensis Shih (1995: 195) , but the former species has much smaller flower-heads and unequal ribs on achenes, and broader leaves ( Fig. 2B ). The molecular phylogenetic analysis based on nuclear ITS region and three plastid genes (Y.L. Peng et al. unpubl. data) supports the position of Youngia purpimea as a member of Youngia and resolves it as sister to Y. szechuanica . It should be the second member of “ Y. sect. Hieraciella Babcock et Stebbins” (1937: 25), nom. inval. Possibly, this species represents a young lineage diverged from its ancestor Y. sect. Youngia and is endemic to the Huagaoxi Nature Reserve in southern Sichuan ( Fig. 2A ).

Figures

FIGURE 1. Line drawing of Youngia purpimea Y.L. Peng, W.B. Ju, X.F. Gao & Y.D. Gao. A. Floret. B. Achene. C. Pappus. D. Ligule of a floret. E. Anther. F. Immature achene enlarged. G. Type image. H. Involucral bracts (A–F drawn by Y.L. Peng based on the holotype).

FIGURE 2. Photographs of Youngia purpimea Y.L. Peng, W.B. Ju, X.F. Gao & Y.D. Gao.A. Habitat in moist slope. B. Capitula of Youngia purpimea. C. Florets. D. Abaxial view of leaves. E. Brown-woolly caudex. (Photos by W.B. Ju from Huagaoxi Nature Reserve, Xuyong County, Longfeng Town).