Hypericum trigonum (Nomenclature)
Perennial herb 0.25-0.4 m tall, erect from short creeping and rooting base, with stems unbranched below inflorescence or with slender ascending or spreading branches from up to c. 5 upper nodes. Stems terete, eglandular; internodes 20-43 mm, longer than or equalling leaves. Leaves sessile, lower not smaller but ascending and soon deciduous; lamina 20-30 ´ 9-15 mm, oblong or oblong-ovate to triangular-ovate, paler beneath, not glaucous, plane, subchartaceous; apex rounded to obtuse, margin entire, base broadly cuneate to shallowly cordate; venation: 4 pairs of main laterals from lower half of midrib, with tertiary reticulation dense; laminar glands punctiform, all pale and very small or all black; intramarginal glands black, dense. Inflorescence 4-c. 15-flowered from terminal node, with flowering branches from up to 4 nodes below, the whole corymbiform to cylindric; pedicels 1-2.5(-5, central flower) mm; bracts narrowly lanceolate to linear, black-glandular-ciliate and -auriculate (cilia long), persistent. Flowers 15-c. 25 mm in diam., stellate or reflexed; buds cylindric, rounded. Sepals 5, equal, erect in bud and fruit, 6-7 ´ 1.5-2 mm, narrowly oblong to elliptic-oblong or lanceolate, acute, glandular-ciliate; veins 5, branching and sometimes reticulating towards margin; laminar glands all pale or parts black, linear or interrupted; marginal glands black, on cilia. Petals 5, golden yellow, not tinged red in bud, 9-11 ´ 2.5-4.5 mm, c. 1.5(-2?) ´ sepals, narrowly oblong-elliptic to lanceolate-elliptic, acute (i.e. with prominent apiculus), margin entire, laminar glands few, pale, linear and sometimes black, 1-3, subapical; marginal gland solitary, in apiculus, black. Stamens c. 25-35, '3'-fascicled, longest 7-9 mm, c. 0.75-0.8 ´ petals; anther gland black. Ovary 3-locular?, c. 4-5 ´ 1.8-2 mm, narrowly ovoid-ellipsoid; styles 3, 4-5 mm, about equalling ovary; stigmas narrowly capitate. Capsule 7-8 ´ c. 4.5 mm, broadly ellipsoid, c. 1-1.5 ´ sepals; valves with numerous longitudinal vittae. Seeds not seen.
Marshes and wet meadows?; 2600-3650 m.
China (NW. Yunnan).
The H. trigonum group (Spp. 3-5), with the closely allied H. monanthemum group (Spp. 1-2), would appear to be related to H. przewalskii and to be derived from it along with, but separately from, the H. seniawinii group (Sect. Elodeoida) (see p. ). Although members of both groups have penetrated westward along the Himalayan Range, the H. seniawinii group is basically south-eastern and upland and the montane species are derivative. The H. trigonum group, on the other hand, is basically south-western and montane. Both groups contain variable taxa that are sometimes difficult to separate specifically, but H. trigonum and its relatives are particularly complex in this regard. The group comprises H. trigonum (NW. Yunnan), H. himalaicum (Pakistan to NW. Yunnan and adjacent Sichuan) and H. ludlowii (Yunnan, SE. Xizang and Bhutan). H. trigonum is basic to the group, being most similar to the long-styled form of H. monanthemum, and the two other taxa are derived from it. The problem is to decide whether there are three species or one species with three subspecies or something in between; and it is complicated by a population in extreme northern Myanmar and adjacent Arunachal Pradesh that is intermediate in some respects between H. trigonum and H. himalaicum. Short of making four subspecies, which would not, I think, be a satisfactory reflection of the situation, it seems best to recognise three species and place the intermediate population in H. himalaicum, despite the long distance between its area (Arunachal Pradesh / Myanmar frontier) and that of the most primitive form of H. himalaicum proper (central Nepal).