Large Flowered St John's Wort

Shrubs, 1-1.8 m tall; branches erect or arching. Stems 4-lined and ± ancipitous when young, becoming 2-lined, eventually terete; internodes 1-4 cm, shorter than to exceeding leaves. Leaves with petiole 0.5-1.5 mm; blade elliptic or lanceolate to ovate or triangular-ovate, 2-5.8 × 0.6-3 cm, thickly papery, abaxially paler but not or scarcely glaucous; laminar glands dots and short streaks; abaxial glands ± dense; main lateral veins 3- or 4(or 5)-paired, tertiary reticulation obscure or invisible; base cuneate or subangustate to rounded, apex acute to obtuse or rarely rounded-apiculate. Inflorescence 1-7(-11)-flowered, from 1(or 2) nodes, nearly flat-topped; bracts deciduous, narrowly lanceolate to subleaflike. Pedicels 5-10 mm. Flowers 4-6.5 cm in diam., stellate; buds narrowly ovoid, apex acute to subacuminate. Sepals spreading, equal, narrowly ovate to lanceolate, 0.7-1.5 cm × 2.5-7 mm, laminar glands lines, margin entire, apex acute to acutely acuminate. Petals bright golden yellow, sometimes becoming recurved, obovate-oblong to obovate, 2.4-4 × 1.6-2.5 cm, ca. 3 × as long as sepals; margin minutely glandular-denticulate toward apex; apiculus acute. Stamen fascicles each with 35-50 stamens, longest 1.8-2.9 cm, 0.7-0.8 × as long as petals. Ovary ovoid-pyramidal to narrowly ovoid, 6-8 × 4-6 mm; styles 8-10 mm, 1.2-1.35 × as long as ovary, free, erect, slightly outcurved at apex. Capsule ± narrowly ovoid-pyramidal to ovoid, 1.7-2 cm × 8-10 mm, turning bright red during maturation. Seeds dark purplish brown, 2-3.2 mm, narrowly winged; testa nearly smooth. Fl. May-Jul(-?Aug), fr. Aug-Sep. 2n = 36*, 40*.

Guangxi, Guizhou.

● Pastures, hillsides, streamsides, among rocks; 1500-2000 m.

Norysca kouytchensis (H. Léveillé) Y. Kimura.

Hypericum kouytchense, the large-flowered St John’s wort, is a species of flowering plant in the family Hypericaceae, native to Western China. Growing up to 3 ft (0.91 m) tall and 5 ft (1.5 m) wide, it is a semi-evergreen rounded shrub with blue-green leaves and large yellow flowers with prominent stamens, appearing in midsummer. Flowers are followed by red seed capsules in autumn. Where conditions are favourable it can retain its leaves all year.

The Latin specific epithet kouytchense is a westernisation of Guizhou, a southwestern province of China identified as a hotspot for biodiversity.

This plant, which is hardy down to −15 °C (5 °F), is cultivated in temperate regions. In the UK it has gained the Royal Horticultural Society’s Award of Garden Merit. It has been reported as invasive in Hawaii.