Hypericum attenuatum Fisch. ex Choisy

Hypericum attenuatum is variable but is distinguishable from all other mainland herbaceous species except H. perforatum by the 2-lined stem internodes. It would seem to be one diploid parent of the amphidiploid H. perforatum (the other being H. maculatum subsp. immaculatum).

Herbs, perennial, 10-45(-70) cm tall, erect from rootstock or creeping rhizomatous base; stems numerous to few, cespitose, much branched. Stems 2-lined, with black glandular dots and streaks on lines and often sparsely (reddish or black) elsewhere. Leaves sessile; blade elliptic to oblong or oblanceolate or rarely ovate, (0.8-)1.5-3.1(-3.8) cm × (3-)5-12(-15) mm; thickly papery, abaxially paler; laminar glands dots, small, pale and black, few or scattered, mainly distal; intramarginal glands black, spaced; main lateral veins 2-paired, tertiary reticulation dense but often rather obscure and apparently lax; base subcordate to cuneate, margin entire and plane; apex obtuse to rounded. Inflorescence (1 or) few- to many-flowered from 1-4 nodes, sometimes with flowering branches from up to 4 nodes below, the whole cylindric to pyramidal; bracts and bracteoles oblong-elliptic, margin entire. Flowers 1.3-2(-2.5) cm in diam., stellate; buds ovoid, apex subacute to acute. Sepals free, erect, triangular-ovate to lanceolate, unequal to subequal, (3.5-)5-10 × 1-4 mm; laminar glands pale, streaks to dots and black dots, scattered, rather sparse or rarely absent; intramarginal and marginal glands black, dots, sparse, distal; margin entire, apex acute to subacuminate; veins 5-7. Petals ?golden yellow, tinged red in bud, oblong-obovate, 0.8-1.2 cm × 4-7 mm, 2.4-3 × as long as sepals, asymmetric; laminar glands black, dots to streaks, scattered; marginal glands black, distally dense; margin entire. Stamens ca. 90, apparently 3-fascicled, longest 8-10 mm, 0.7-0.8 × as long as petals. Ovary narrowly ovoid; styles 3, free, 4-4.5 mm, 1.3-1.6 × as long as ovary, widely spreading. Capsule broadly ovoid or oblong-ovoid to narrowly conic, (4-)6-10 × 2-6 mm, 2-3 × as long as sepals; valves occasionally with a few black longitudinal glandular streaks. Seeds medium brown, 0.7-1.1 mm; testa finely linear-foveolate. Fl. Jun-Aug, fr. Jul-Sep. 2n = 16.

Fields, pastures, steppes, grassy and dry stony slopes, pebble shores, forest margins, clearings; sea level (Liaoning) to 2000 m (Guizhou). Anhui, Fujian, Gansu, Guizhou, Hebei, Heilongjiang, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Jilin, Liaoning, Nei Mongol, Shaanxi, Shanxi, Sichuan, Zhejiang; also recorded from Guangdong, Guangxi [Korea, Mongolia, Russia (Far East, E Siberia)].

Hypericum attenuatum, is a species of perennial herbaceous flowering plant in the family Hypericaceae.