Hypericum hayatae Y. Kimura; H. nagasawae var. nigrum Y. Kimura; H. randaiense Hayata; H. suzukianum Y. Kimura; H. taiwanianum Y. Kimura; H. taiwanianum var. ohwii Y. Kimura.
Herbs, perennial, 5-35 cm tall, suberect to ascending from creeping branching rooting base; stems solitary or ± cespitose, unbranched or ± branched above. Stems 2-lined, eglandular. Leaves sessile or subsessile; blade ovate or oblong to elliptic or oblanceolate or linear, (0.3-)0.8-2.5 cm × 3-12 mm; thickly papery to subleathery, abaxially glaucous or sometimes minutely papillose; laminar glands pale, dots, rather sparse, prominent above; intramarginal glands black, dense or irregular; main lateral veins 3- or 4-paired, sometimes forming ± marked submarginal vein, tertiary reticulation lax or obscure; base cuneate to angustate, margin entire and recurved, apex acute to rounded. Inflorescence 1-11-flowered from 1 or 2 nodes, sometimes with flowering branches from 1 or 2 nodes below, the whole nearly flat-topped; bracts and bracteoles lanceolate to linear, margin entire. Flowers 1.5-2.7 cm in diam., ± stellate; buds ovoid to ellipsoid, apex obtuse. Sepals free, ascending in bud, spreading in fruit, ovate-lanceolate to ± narrowly oblong, equal, 3-7.5 × 0.8-2.5 mm; laminar glands pale or rarely black, streaks or rarely lines to dots; marginal glands black and sometimes pale, regular or irregular, immersed or rarely on cilia, or absent; margin entire or rarely with 1 or 2 glandular cilia, apex obtuse to acute; veins 5. Petals ?bright yellow, ?tinged red in bud, obovate or oblong-obovate to oblanceolate, 0.8-1.5 cm × 4-7 mm, 2-2.5 × as long as sepals; laminar glands pale and rarely black, lines to dots, or rarely absent; marginal glands black, sessile or occasionally on cilia, distal or subapical; margin usually entire. Stamens 40-80, not or obscurely fascicled, longest 4.5-8 mm, 0.6-0.8 × as long as petals. Ovary narrowly ovoid to ellipsoid-ovoid, 2-2.5 × 1-1.5 mm; styles 3, 3.5-7 mm, 1.3-3 × as long as ovary, ± spreading from near base. Capsule narrowly to broadly ovoid, (5-)6-7 × 3.5-5 mm, 1-1.5 × as long as sepals. Seeds dark brown, ca. 1 mm, scarcely carinate; testa finely scalariform-reticulate. Fl. Jul-Aug, fr. Aug-Oct. 2n = 36*.
Stony or rocky slopes, roadsides, conifer forests; 2300-4000 m. Taiwan (central mountains).
The variation from the mainly northern, broad-leaved form, with sepals and styles ca. 1.3 × as long as the ovary (Hypericum nagasawae), to the southern, narrow-leaved form, with apically acute sepals and styles ca. 2 × as long as the ovary or more (H. randaiense), appears to be continuous; and indeed the trends in leaf form, sepal shape, and style length are only partially correlated. It is not possible, therefore, to recognize H. randaiense as a distinct species. Similarly, plants described as H. suzukianum and H. hayatae, respectively, are more extreme forms of trends within H. nagasawae; and the occasional forms with black-glandular-ciliate sepal margins (H. taiwanianum) are linked to the more typical forms by specimens with one or two glandular cilia on each sepal margin.