Youngia muliensis S. Y. Liao & Y. S. Chen 2024, sp. nov.

Youngia muliensis S. Y. Liao & Y. S. Chen, sp. nov. (Figures 2–3) Type:— CHINA. Sichuan, Muli county, Mianbu cun, near G227, 27.734492° N, 101.235634° E, at the edge of a thicket on a steep rocky slope, elev. 2983 m, 4 August 2023, You-Sheng Chen & Shu-Yuan Liao ML 20230934 (holotype IBSC; isotypes IBSC, PE). Description:—Herbs perennial, 15–40 cm tall. Taproot with shoot-bearing lateral roots. Caudex often with residues of old leaf bases. Stem usually solitary, slender, erect, sparsely branched from near base or middle, sparsely white hairy, and almost leafless. Basal leaves a few; lamina broadly ovate, ovate-elliptic, elliptic, orbicular, 1.5–7 × 1–2.5 cm, undivided or sometimes divided with one pair of auriculate lobes; lobes ca. 0.5–1.5 × 0.5–1.5 cm; base deeply cordate and revolute; petiole 2–10 cm long, unwinged, densely white pubescent, purplish red, and canaliculate adaxially; margin entire to sinuate-dentate, apex obtuse to acute; both surfaces densely pubescent. Lower or middle stem leaves (if present) narrowly elliptic, 3–6 × 1.5–2 cm, undivided or sometimes lobed, both surfaces densely pubescent; base attenuate into a petiole-like portion; margin distantly dentate; apex acute. Middle or upper stem leaves (if present) narrowly linear, reduced in size. Synflorescence corymbiform to paniculiform-corymbiform, with few to some capitula. Capitula with 9–10 florets; peduncle capillaceous, 0.5–3 cm long, slender, ± white arachnoid hairy. Involucre cylindric, 6–9 mm long. Phyllaries dark green, abaxially glabrous; outer ones 3–4, triangular to ovate, longest ones ca. 2 mm long, apex acute to obtuse; inner ones ca. 8, lanceolate, 6–9 × 1 mm, adaxially appressed hairy, midvein subapically almost plane, margin white-membranous, apex acute. Florets yellow; corolla tube ca. 2 mm long; ligule ca. 8 mm long, ca. 3 mm wide, apex 5-toothed; anther tube yellow, ca. 3.5 mm long. Style branches yellow upon drying, ca. 1.5 mm long. Achenes not seen when mature. Pappus white, ca. 4 mm long. Flowering July–August. Phenology:—Flowering from July to August. Etymology:—The specific epithet refers to the type locality of this new species, Muli county in Sichuan, China. Vernacular name:— †Ħflfi̿, mù lǐ huánɡ ān cài in Chinese Pinyin. Distribution and habitat:—Only known from the type population. The plants grow at the edge of a thicket on a steep, rocky slope near the forest edge (Figure 3A, B, C), at an elevation of about 2983 m in Muli county, Sichuan, China (Figure 4). Notes:—Characters such as the caudex often bearing residues of old leaf bases, the slender, erect stem being sparsely branched, and the presence of few narrowly linear leaves or a nearly leafless condition, indicate that the new species belongs to Youngia sect. Mesomeris Babcock & Stebbins (1937: 59). Comparisons of the morphological characters between Y. muliensis and Y. pilifera are presented in Table 1. Table 1. Comparisons of morphological characters between Youngia muliensis and Y. pilifera.