Hypericum hookerianum (Nomenclature)
Shrub 0.3-2 1 m tall, bushy, round-topped, with branches erect to spreading. Stems red to yellowish, 4-lined and ancipitous when young and usually soon terete, or always terete; internodes 12-60 mm long, shorter than to exceeding leaves; bark grey-brown. Leaves petiolate, with petiole 1-4 mm long; lamina (17-)25-78 x (7-)10-32 mm, narrowly lanceolate or oblong-lanceolate to broadly ovate, acute or obtuse to apiculate or rounded, margin plane, base narrowly cuneate to subcordate, paler or ± glaucous beneath, chartaceous; venation: (2)3-4 pairs main laterals, with midrib pinnately branched above, without visible tertiary reticulum; laminar glands short to very short streaks and dots; ventral glands absent or ± dense. Inflorescence 1-5-flowered, from apical node, subcorymbiform; pedicels 3-16 mm long; bracts lanceolate or narrowly oblong to obovate-spathulate, deciduous. Flowers 30-60 mm in diam., ± deeply cyathiform; buds broadly ovoid to subglobose, broadly obtuse to rounded. Sepals 5-10 x 4-8 mm, free, (often broadly) imbricate, subequal, erect in bud and fruit, obovate or obovate-spathulate to subcircular or elliptic or oblong- elliptic, rounded or rarely rounded-apiculate, with margin entire or rarely very finely eroded-denticulate; midrib visible or ± obscure, veins often prominent, especially in fruit; laminar glands linear, sometimes interrupted near apex, numerous. Petals deep golden to pale yellow, not tinged red, markedly incurved, 15-30 x 15-25 mm, c. 3 x sepals, broadly obovate to subcircular, with apiculus subterminal, obtuse to rounded, or absent; margin entire, eglandular. Stamen fascicles each with 60-80 stamens, longest 5-9 mm long, 0-25-0-35 x petals; anthers golden yellow, sometimes tinged red ? Ovary 5-7(-8) x 4-5(-6) mm, broadly ovoid, acute; styles 2-4(-7) mm long, 0.35-0.7(-0-9) x ovary, free, gradually outcurved towards apex; stigmas narrowly capitate. Capsule 9-17 x 7-12 mm, ovoid to ovoid-conic. Seeds dark reddish-brown, 0.7-1 mm long, cylindric, not or scarcely carinate, shallowly linear- reticulate.
2n = 20?
Dry to moist, open to half-shaded habitats (grassy or rocky slopes or cliffs, thickets, open forest, forest margins); 1200-3000 m.
China (west Yunnan, south-east Xizang [Tibet]), Vietnam (north), Thailand (north), Burma (north, central, and Mt. Victoria), India (Arunachal Pradesh, Bengal, Meghalaya, Manipur; Mysore, Tamil Nadu), Bhutan, Tibet (south-east), Sikkim, Nepal (east).
H. hookerianum is a variable species related to H. fosteri. From Yunnan, where the form most similar to that species occurs in the Dali region, it shows clinal variation in two directions: (i) through central Burma ('rodgersii’?) , Manipur and Meghalaya to the Himalayan range at Bhutan and thence west to central Nepal and east to northern Burma; (ii) through central Burma to northern Thailand ('garretti’), western Burma (Mt. Victoria) and southern India. Both clines show trends from red 4-angled stem, small acute ovate-lanceolate leaves and large flowers with rounded- apiculate sepals (Yunnan) to orange terete stem, large narrowly lanceolate rounded leaves and small flowers with obovate-spathulate rounded sepals. In cline (i) the leaves in the early stages are glaucous beneath with dense ventral glands, whereas the later stages (most Himalayan specimens) resemble plants from Thailand, Mt. Victoria and southern India in having leaves pale beneath without ventral glands. In Meghalaya there is a local variation in which the leaves become very broadly ovate and the plant looks superficially like 47. H. latisepalum. These variation trends appear continuous, so that, despite the wide range of H. hookerianum, no infraspecific taxa can be recognised. Plants have been introduced into cultivation, however, from two distinct parts of the range, viz. the (i) Himalaya and Mt. Victoria (showing advanced characters as described above) and (ii) central Burma. The latter form has been named var. rodgersii and merits recognition as a cultivar (Map 20):
H. hookerianum has been confused with H. choisyanum, as they both occur in similar habitats in the eastern and central Himalaya. They are, however, nearly always easily distinguishable morphologically (see p. xxx); and H. hookerianum occurs at lower, though overlapping, altitudes (1200-3300 m as against 2400-4800 m for H. choisyanum in the same area).