Homostylium lavandulifolium Z. X. Fu. A. Habit 2025, comb. nov.

5.Homostylium lavandulifolium(Hand. - Mazz.) Z. X. Fu comb. nov. Figs 12, 13, 14 ≡ Aster lavandulifolius Hand. - Mazz., Notizbl. Bot. Gart. Berlin-Dahlem 13: 609. 1937. ≡ Sinosidus lavandulifolius (Hand. - Mazz.) G. L. Nesom, Phytoneuron 2020-64: 14. 2020. Type: China, Sichuan, Muli, watershed of the Shou-chu river and Shou-chu valley, in dry gorge, alt. 2435–2900 m, June 1928, J. C. F. Rock 16273 (lectotype, designated by Nesom (2020 g), W, not seen; isolectotypes, US 00145655!, A 00003817!, GH 00003818!, E 00413420!) (Suppl. material 1: figs S 31 – S 34). Type. China • Sichuan, Muli, watershed of the Shou-chu river and Shou-chu valley, in dry gorge, alt. 2435–2900 m, June 1928, J. F. Rock 16273 (lectotype, designated by Nesom (2020 g), W, not seen; isolectotypes, US 00145655!, A 00003817!, GH 00003818!, E 00413420!) (Suppl. material 1: figs S 31 – S 34). Description. Shrubs, 48–124 cm tall. Leaves subleathery, narrowly linear, 1–4 (- 5.4) × 0.1–0.3 (- 0.53) cm, margins entire, revolute; midvein prominently glabrous, venation pinnate; adaxially green, rugose, resinous, very sparsely sericeous to nearly glabrous, papillate protrusions; abaxially densely gray-white tomentose; upper leaves smaller. Capitula 6–9 mm in diameter, 3–6 at ends of lateral branches or numerous in ± densely corymbiform synflorescences, terminal on current-year branches. Peduncles 2–6 mm long, with subulate bracteoles. Involucres obconical to campanulate, 5–7 × 4–7 mm. Phyllaries 4–5 - seriate, imbricate, outer phyllaries ovate, ca. 1 mm × 0.5 mm, inner phyllaries longer, linear-lanceolate, sparsely tomentose, 4–5 × 0.7–0.9 mm. Distribution. Endemic to China, W Sichuan (Daocheng, Jiulong, Kangding, Muli, Yajiang), and NW Yunnan (Fig. 13). Habitat. Subalpine stony slopes, riverbanks, and shrublands of aridly hot river valleys. 2000–2900 m. Phenology. Flowering June to August. Fruiting August to September. Specimens examined. China • Sichuan: Daocheng, Sichuan Veg. Exped. 2109 (CDBI); Jiulong, S. Jiang et al. 3918 (PE), T. T. Yu 6694 (PE), X. J. Yang 3935 (PE); Kangding, Z. J. Zhao et al. 114731 (CDBI), Y. S. Chen 7566 (PE); Muli, T. T. Yu 5894 (PE, IBSC), Y. S. Chen 7099 (PE), Y. S. Chen 7507 (PE), J. C. F. Rock 16273 (W, US 00145655, A 00003817, GH 00003818, E 00413420), FLPH Sichuan Exped. 151845 (PE); Yajiang, G. J. Zhang 170 (PE), Z. T. Guan 56-0438 (PE), Z. P. Huang et al. 552 (PE), S. Jiang et al. 3202 (PE), Wei L. Chen et al. 6604 (PE). Etymology. The name “ lavandulifolium ” is derived from the Latin “ lavandula ”, referring to the genus Lavandula L., combined with the neuter suffix “ - folium ”, meaning “ leaf ” or “ have the form of ”. The specific epithet likely refers to the linear leaf shape of this species, resembling the distinctive form of Lavandula. Notes. This species is particularly distinctive within Homostylium. The leaves of this species are narrowly linear, with revolute margins. The abaxial surface is pubescent, with prominent midrib, and cylindric achenes.