Description from Flora of China
Hypericum chinense Linnaeus, Syst. Nat., ed. 10, 2: 1184. 1759, not Osbeck (1757), nor Retzius (1788); H. chinense subsp. latifolium Kuntze; H. chinense subsp. obtusifolium Kuntze; H. chinense subsp. salicifolium (Siebold & Zuccarini) Kuntze; H. chinense var. salicifolium (Siebold & Zuccarini) Choisy; H. monogynum var. salicifolium (Siebold & Zuccarini) André; H. salicifolium Siebold & Zuccarini; Komana salicifolia (Siebold & Zuccarini) Y. Kimura ex Honda; Norysca chinensis (Linnaeus) Spach; N. chinensis var. salicifolia (Siebold & Zuccarini) Y. Kimura; N. salicifolia (Siebold & Zuccarini) K. Koch.
Shrubs, 0.5-1.3 m tall, bushy or usually with branches lax, spreading. Stems 2(-4)-lined and ancipitous when young, soon terete; internodes 1-5 cm, shorter than leaves. Leaves with petiole 1.5-2 mm; blade oblong to elliptic, 2.5-5 × 1.2-2.3 cm, thickly papery, abaxially paler but not glaucous; laminar glands very small dots; abaxial glands absent; main lateral veins 2- or 3-paired, all or upper sometimes uniting with midvein branches to form ± arched intramarginal vein, tertiary reticulation very dense, not very conspicuous; base cuneate to subangustate, apex acute to rounded. Inflorescence 1-15(-30)-flowered, from apical node, lax, shallowly round-topped, sometimes also from uppermost 1-3 nodes, rarely with 1 or 2 pairs of flowering branches; bracts caducous, linear-lanceolate, small. Pedicels 0.8-2.8(-5) cm. Flowers 3-6.5 cm in diam., stellate; buds ovoid, apex subacute to obtuse. Sepals ± spreading, broadly to narrowly elliptic or oblanceolate, equal to unequal, 4.5-13 × 1.5-6 mm; laminar glands basally lines to streaks, dots toward apex, margin entire, apex acute to rounded. Petals golden yellow to lemon yellow, triangular-obovate, 2-3.4 × 1-2 cm, 2.5-4.5 × as long as sepals; margin entire, eglandular; apiculus lateral, acute to rounded or obsolete. Stamen fascicles each with 25-35 stamens, longest 1.8-3.2 cm, ca. as long as petals. Ovary ovoid or ovoid-conic to subglobose, 2.5-5 × 2.5-3 mm; styles 1.2-2 cm, 3.5-5 × as long as ovary, united nearly to apices then outcurved or very rarely to half free. Capsule broadly ovoid or rarely ovoid-conic to subglobose, 6-10 × 4-7 mm. Seeds dark reddish brown, ca. 2 mm, narrowly carinate; testa linear-reticulate. Fl. May-Aug, fr. Aug-Sep. 2n = 42*.
Hypericum monogynum is very variable, but there are no gaps in the variation that would allow infraspecific classification. Four main forms can be recognized:
(i) Leaves elliptic to oblanceolate, base cuneate, apex acute; inflorescence very lax; sepals narrowly elliptic, apex acute ("salicifolium"). W Hubei, Shaanxi, Sichuan.
(ii) Leaves narrowly oblong to lanceolate, base usually rounded, apex obtuse to rounded; inflorescence less lax; sepals narrowly oblong, obtuse ("obtusifolium"). E Hubei and Jiangxi southward and eastward to the coast; Taiwan, where the leaves are oblanceolate.
(iii) Leaves broadly oblong to broadly elliptic or lanceolate, base cuneate to cordate, apex acute to rounded; sepals broadly elliptic to broadly oblong or leaflike ("latisepalum"). W Hubei, Sichuan; also Guizhou and Shandong (probably introduced).
(iv) Leaves broadly elliptic-oblong to triangular-ovate or ovate, base broadly cuneate to rounded, apex obtuse to rounded; sepals narrowly elliptic, apex acute ("ovatum"). Sichuan.
● Mountain slopes, roadsides, thickets in dry habitats; sea level to 200 m in lowland provinces, but up to 1500 m in Sichuan. Anhui, Fujian, Guangdong, Guangxi, Guizhou, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Shaanxi, Shandong, Sichuan, Taiwan, Zhejiang [Japan (naturalized); widely cultivated in S Africa, E and S Asia, Australia, Central America, N and W Europe, Mauritius, and the West Indies].