Homostylium argyropholium (Hand. - Mazz.) Z. X. Fu, 2025

Chen, Xinyu & Fu, Zhixi, 2025, Resurrection of the genus Homostylium Nees for the former Aster ser. Albescentes Y. Ling (Astereae, Asteraceae), with an updated generic synopsis, PhytoKeys 259, pp. 27-66 : 27-66

2. Homostylium argyropholium (Hand. - Mazz.) Z. X. Fu comb. nov.

Figs 4 , 5

≡ Aster argyropholis Hand. - Mazz. , Acta Horti Gothob. 12: 208. 1938. ≡ Sinosidus argyropholis (Hand. - Mazz.) G. L. Nesom , Phytoneuron 2020-64: 13. 2020. Type: China, Sichuan, Kangding (Tatien-lu), frutex fere metralis in declivo aprico, 2 Jul 1922, H. Smith 2258 (holotype, UPS, v- 080214!) (Suppl. material 1: fig. S 25).

Type.

China • Sichuan, Kangding (Tatien-lu), frutex fere metralis in declivo aprico, 2 Jul 1922, H. Smith 2258 (holotype, UPS, v- 080214!) (Suppl. material 1: fig. S 25) .

Description.

Shrubs, 93–228 cm tall. Leaves subleathery, alternate, elliptic, oblong, or lanceolate-ovate, 1–4 × 0.3–1.6 cm; midvein abaxially prominent, lateral veins apparent, pinnate; margin subundulate to entire, revolute, glandular-punctate, upper leaves smaller; adaxially green, moderately scabridulous, minutely glandular, resin-dotted, scabrous; abaxially densely lanate or greyish-white arachnoid-tomentose. Capitula 4–10 (- 20), with 15–20 ray florets, in corymbiform synflorescences, terminal on axillary branches. Peduncles slender, 2–7 mm, bracteoles linear. Involucres campanulate, ca. 5 mm long, 8 mm in diameter. Phyllaries 4–5 seriate, imbricate, pubescent to glabrescent, outer phyllaries oblong, 1 × 0.5 mm, inner phyllaries ovate, 4–5 × 1 mm.

Distribution.

China, S and W Sichuan, SE Xizang, NW Yunnan (Fig. 5 ).

Habitat.

Alpine and subalpine slopes, under forests, grasslands, riverbanks. 2100–3100 m.

Phenology.

Flowering May to October. Fruiting August to October.

Etymology.

It is derived from the Greek “ argyros ”, meaning “ silver ”, and “ pholis ”, meaning “ skin ” or “ scale ”, combined with the Latin neuter suffix “ - um ”. The specific epithet likely refers to the silvery, scale-like, glandular punctate on the leaves.

Notes.

This species is similar to Homostylium albescens var. discolor . However, it can be distinguished by its fewer capitula borne at the branch tips, narrower involucre, and white buds in the leaf axils. H. polium bears soft and white arachnoid-tomentose on the abaxial leaves, particularly resembling H. argyropholium . However, it has much smaller leaves, and inflorescences borne on lateral branches, allowing for easy differentiation from H. argyropholium .

Figures

Figure 4. Homostylium argyropholium (Hand. - Mazz.) Z. X. Fu. A. Habit; B. Habitat; C. Capitula (lateral view, showing the involucre); D. Abaxial surface of leaves. Photographed by Z. X. Fu from Z. X. Fu 2944 (PE).

Figure 5. Distribution of Homostylium argyropholium. China is centrally located on the map.