Author

G & P Jürgens

Hydrangeaceae

Hydrangea macrophylla

by G & P Jürgens

(Thunb.) Ser.

Bhutan2015 285
Bhutan Zhemgang 910m, October

Description

Hydrangea macrophylla is a deciduous shrub of East Asian origin, now among the most widely cultivated ornamental hydrangeas worldwide; this is reflected in its very large GBIF record (over 16,000 occurrences) spanning Japan, China, Korea, much of Europe, the Americas, Australasia and beyond, where most points represent garden or naturalised plants. In the Himalaya it occurs chiefly in cultivation and around settlements, growing in moist, humus-rich, partially shaded ground at low to mid elevations. The documented plant from Zhemgang in Bhutan at 910 m in October indicates such a subtropical montane setting, flowering and fruiting late in the season in the warm-temperate belt.

The species is a rounded, much-branched shrub with stout, glabrous stems and large, opposite, broadly ovate to elliptic leaves that are coarsely serrate, glossy and somewhat fleshy. The inflorescence is a broad, flattened to globose terminal corymb; in wild and lacecap forms the small fertile flowers occupy the centre while showy sterile flowers with four enlarged, petaloid sepals form the margin, whereas cultivated mopheads are dominated by sterile flowers. Corolla colour ranges from white through pink to blue, the latter influenced by soil acidity and available aluminium. The fruit is a small ribbed capsule with numerous minute seeds.

Within Hydrangeaceae the species belongs to the mophead and lacecap group and has given rise to innumerable cultivars. Its sterile marginal flowers act as visual attractants for pollinators of the inner fertile florets, and its pigment chemistry makes flower colour a notable indicator of substrate pH. Wild populations are restricted to coastal Japan, while elsewhere occurrence is overwhelmingly anthropogenic.

Author: (Thunb.) Ser. · Sources: POWO (Kew), GBIF, Flora of China Vol. 8, Flora of Bhutan Vol. 1, McClintock A Monograph of the Genus Hydrangea

Hydrangeaceae

Hydrangea stylosa

by G & P Jürgens

Hook. f. & Thomson

Bhutan2012 692
Bhutan Galephu, 850m September
Bh09 216 G363
Bhutan Dochu-La, 3000m June
Bh09 217 P364 2
Bhutan Dochu-La, 3000m June

Description

Hydrangea stylosa Hook.f. & Thomson is a Sino-Himalayan shrub recorded by GBIF from China, Bhutan, India, Vietnam and Japan, with cultivated occurrences from Canada and New Zealand, totalling about 85 records. It occupies a broad altitudinal range in moist broad-leaved and mixed forest, thickets and forest margins, on shaded slopes and along ravines. The Bhutanese material spans this amplitude strikingly, with collections from Galephu at 850 m in September and from the Dochu-La at 3000 m in June, showing occurrence from low submontane forest up into the cool temperate zone.

It is a deciduous shrub with terete branches, the young growth often pubescent and the bark exfoliating on older stems. The leaves are opposite, ovate to oblong-lanceolate, with a serrate margin, an acuminate apex and pinnate venation, pilose along the veins beneath. The inflorescence is a terminal corymbose cyme bearing two kinds of flowers: numerous small fertile flowers with minute petals, and a marginal ring of showy sterile flowers whose enlarged, petaloid white to pinkish sepals attract pollinators. The fertile flowers are notable for their elongate, persistent styles, emphasised by the epithet stylosa; the fruit is a small ribbed capsule opening between the styles.

Within Hydrangea, H. stylosa belongs to the lacecap-type species, in which marginal sterile flowers advertise the fertile centre to insects. Its distribution forms part of the eastern Himalayan to Sino-Japanese floristic continuum, and the species is of horticultural interest, accounting for the cultivated records beyond its native range. As a forest understorey shrub it depends on humid montane woodland.

Author: Hook. f. & Thomson · Sources: POWO (Kew), GBIF, Flora of Bhutan Vol. 1, Flora of China Vol. 8, McClintock monograph of the genus Hydrangea, Flora of Nepal

Araliaceae

Hydrocotyle javanica

by G & P Jürgens

Thunb.

Bhutan2015 150
Bhutan Zhemgang 900m, October

Description

Hydrocotyle javanica is a widespread perennial herb of tropical and subtropical Asia and the western Pacific, recorded from the Himalaya (Nepal, NE India, Bhutan) through southern China, Taiwan, Japan and Korea to Sri Lanka, Myanmar, Indochina, Malesia, the Philippines, New Guinea, Australia and Fiji; with 2,061 GBIF occurrences it is among the better-documented members of its genus. It favours moist, shaded ground along streams, forest floors, seepage banks and damp roadside verges. The Bhutan record from Zhemgang at about 900 m in October places it in warm, humid subtropical forest, where it grows as a creeping ground cover.

It is a creeping to ascending herb rooting at the nodes, with slender, often pilose stems. The leaves are alternate, long-petioled, orbicular to reniform in outline, 2–7 cm wide, palmately 5–7-lobed with the lobes again toothed, cordate at the base, and frequently bearing scattered hairs. The inflorescences are condensed simple umbels, sometimes verticillate along the stem, on peduncles shorter than the petioles; the minute flowers are whitish to greenish, with five petals and an inferior bicarpellate ovary. The fruit is a small, laterally compressed schizocarp, broader than long, the mericarps with conspicuous lateral ribs.

Long placed in Apiaceae, Hydrocotyle is now segregated into Araliaceae (Hydrocotyloideae) on molecular grounds, so the input family is botanically defensible. GBIF lists the name as accepted. The species is highly variable across its enormous range, and several infraspecific taxa have been described; it is common, weedy and of no conservation concern.

Author: Thunb. · Sources: POWO (Kew), Flora of China Vol. 14, Flora of Bhutan Vol. 2, GBIF, Pimenov & Leonov: The Genera of the Umbelliferae (1993)

Fabaceae

Hylodesmum laxum

by G & P Jürgens

(DC.) H.Ohashi & R.R.Mill

Bhutan2012 572
Bhutan Wangdi 2700m, September
Bhutan2012 573
Bhutan Wangdi 2700m, September

Description

Hylodesmum laxum is a widely distributed forest herb of warm-temperate and subtropical Asia, recorded from Japan, China, Taiwan, the Philippines, Indonesia, Papua New Guinea, India, Vietnam, Sri Lanka, Thailand, Nepal and Bhutan, with some 740 georeferenced occurrences. It is a characteristic understorey element of moist broad-leaved and mixed evergreen forests, favouring shaded slopes, forest margins and streamside thickets on humus-rich soils. In the eastern Himalaya it ascends to the middle montane belt, as illustrated by the material gathered near Wangdi in central Bhutan at about 2700 m in September, when it flowers and fruits in the post-monsoon season.

The species is a perennial herb with erect or ascending, slender, ridged stems arising from a woody rootstock. The leaves are pinnately trifoliolate and crowded toward the stem apex, the terminal leaflet rhombic-ovate to elliptic and larger than the lateral ones, acuminate and entire, thinly membranous and sparsely appressed-pubescent. The inflorescence is a lax, elongate terminal raceme or panicle bearing small papilionaceous flowers with a pink to pale purple corolla, the standard obovate and the keel obtuse. The fruit is a flattened, stipitate loment constricted between the segments, the articles covered with uncinate hairs that promote epizoochorous dispersal.

The genus Hylodesmum was segregated from Desmodium by Ohashi and Mill to accommodate species with stipitate, deeply constricted loments and a forest-herb habit, and H. laxum is among its more widespread members. Its very broad transcontinental range, spanning the Himalaya to the western Pacific, points to effective long-distance dispersal by the hooked fruit articles. Locally common and of no immediate conservation concern, its populations nonetheless remain dependent on intact forest cover, and the species is a useful indicator of relatively undisturbed montane woodland.

Author: (DC.) H.Ohashi & R.R.Mill · Sources: POWO (Kew), GBIF, Flora of China Vol. 10, Flora of Bhutan Vol. 1, Flora of Nepal, Ohashi & Mill revision of Hylodesmum (Desmodium group)

Apiaceae

Hymenidium brunonis

by G & P Jürgens

Lindl.

Garw 2005 155 ergebnis ergebnis scaled
Garw 2005 156jpg ergebnis ergebnis scaled
India Garhwal Kuari-Pass 4000m, September

Description

Hymenidium brunonis is a high-alpine umbellifer of the Himalaya, recorded from Pakistan eastward through north-west and central India to Nepal. Long familiar under the name Pleurospermum brunonis, it inhabits open alpine meadows, screes, rocky slopes and moist hollows above the treeline, generally between about 3,500 and 4,800 m. The individual photographed at the Kuari Pass in Garhwal, India, at 4,000 m in September shows the species in its characteristic late-season setting, fruiting as the short alpine summer closes. Its scattered but consistent occurrence across the chain (some 75 georeferenced records) reflects a true alpine specialist of the inner Himalayan ranges.

It is a low, glabrous, somewhat fleshy perennial arising from a stout taproot and a sheath of fibrous remains of old petioles. The leaves are mostly basal, pinnate to bipinnate, the segments oblong and often crowded, the petioles broadly sheathing at the base. The inflorescence is a compound umbel subtended by conspicuous, broad, membranous-margined, often leafy bracts and bracteoles — a diagnostic feature of the group. The small flowers are white to pinkish, with five petals and an epigynous disc. The fruit is an ovoid to oblong schizocarp with prominently winged or ridged mericarps.

The transfer of many Asian Pleurospermum species to Hymenidium follows molecular work resolving the polyphyly of Pleurospermum sensu lato; the conspicuous scarious bracts unite the segregate. As a plant of remote high-elevation habitats it faces little direct pressure, though alpine flora of this belt is sensitive to grazing intensity and to the upslope compression of habitat under a warming climate.

Author: Lindl. · Sources: POWO (Kew), Flora of China Vol. 14, Flora of Pakistan (Umbelliferae), GBIF, Pimenov & Leonov: The Genera of the Umbelliferae (1993)

Hypericaceae

Hypericum hookerianum

by G & P Jürgens

Wight & Arn.

Bhutan2014 8
Bhutan Sandrup 750m, May
Bhutan2014 222
Bhutan Karu-Chu 1800m, May

Description

Hypericum hookerianum is a Himalayan and Sino-Himalayan shrubby St John's wort, native across China, NE India, Nepal, Bhutan and Myanmar, with GBIF recording some 638 occurrences including numerous cultivated and naturalised records from Europe, North America and Australasia. In the wild it grows in forest margins, clearings, scrub and on open rocky slopes. The photographed Bhutanese plants from Sandrup (750 m) and Karu-Chu (1,800 m), both in May, illustrate its wide altitudinal tolerance from the subtropical foothills to the warm temperate belt.

It is an evergreen or semi-evergreen shrub with terete, often reddish branches. The leaves are opposite, ovate to oblong or lanceolate, sessile or nearly so, frequently glaucous beneath and dotted with pale translucent glands. The flowers are large and showy, borne singly or in few-flowered cymes; they are cup-shaped to bowl-shaped, deep golden-yellow, with five broad concave petals and a dense central boss of numerous stamens grouped in five fascicles surrounding a stout ovary with several styles. The fruit is a many-seeded septicidal capsule.

Hypericum hookerianum is a parent of several widely grown ornamental cultivars and hybrids, valued for its robust habit and bold flowers, which accounts for its scattered occurrence well beyond its native range. The translucent and dark glands of the foliage, characteristic of the genus, contain hypericin and hyperforin and related bioactive compounds. Within the large and complex genus Hypericum, the species belongs to the woody section Ascyreia, distinguished by its shrubby habit, large bowl-shaped flowers and fascicled stamens; it is of no conservation concern given its breadth of range and cultivation.

Author: Wight & Arn. · Sources: POWO (Kew), Flora of Bhutan Vol. 1, GBIF, Flora of China Vol. 13, Robson: Studies in the Genus Hypericum (Bulletin of the Natural History Museum)

Hypericaceae

Hypericum oblongifolium

by G & P Jürgens

Choisy

Garh 07 321JPG ergebnis
India Garhwal Maji 2650, June

Description

Hypericum oblongifolium is a shrubby St John's wort of the family Hypericaceae, native to the western and central Himalaya. GBIF records place it principally in India, Pakistan, Nepal and Afghanistan, with scattered records eastward to Bhutan and occurrences elsewhere representing cultivated plants. It grows on open, rocky hillsides, in scrub, along forest margins and on stream banks in the temperate zone, generally between about 1,500 and 3,000 m. The specimen illustrated from Maji in Garhwal, India, at around 2,650 m in June is typical of this sunny, well-drained mid-montane habitat where the shrub flowers in early summer.

The plant is a much-branched, evergreen to semi-evergreen shrub up to about 1–2 m, with reddish, arching, two-lined younger branches becoming terete with age. The leaves are opposite, sessile to subsessile, oblong to oblong-lanceolate, leathery, with translucent glandular dots, and somewhat glaucous beneath. The flowers are large and showy, golden-yellow, borne singly or in few-flowered terminal cymes; they have five spreading petals, numerous stamens grouped into bundles, and a superior ovary crowned by free styles, conforming to the characteristic Hypericum floral plan. The fruit is a septicidal capsule that splits to release numerous small seeds.

Within the large genus Hypericum the species belongs to the predominantly Asian section of woody, large-flowered shrubs and is closely allied to other Himalayan taxa such as H. hookerianum, from which it is separated by leaf shape, branch character and details of the styles. It is valued horticulturally for its abundant bright flowers and is used locally in folk medicine. Widespread and tolerant of disturbed, open ground, it is not considered threatened, and it readily colonises sunny banks and roadside scrub throughout the western Himalaya.

Author: Choisy · Sources: POWO (Kew), GBIF, Flora of Pakistan, Flora of Nepal, Flora of China Vol. 13, Robson: Studies in the genus Hypericum (Guttiferae)

Brassicaceae

Ianhedgea minutiflora

by G & P Jürgens

(Hook.f. & Thomson) Al-Shehbaz & O’Kane

Nepal 99 819 ergebnis
West-Nepal Baga-La-Phedi 4300m, July

Description

Ianhedgea minutiflora is a diminutive, high-alpine crucifer with a broadly Irano-Turanian to western Himalayan distribution, recorded from Afghanistan, Pakistan, northern India, Tajikistan and Iran, and extending eastward into western Nepal. It is a plant of open, stony and gravelly ground, scree slopes, glacial moraines and dry alpine meadows at high elevations, typically between about 3,500 and 4,800 m. The collection from Baga-La-Phedi in West Nepal at 4,300 m in July reflects its occurrence in the cold, well-drained, sparsely vegetated terrain of the upper alpine zone, where the short summer growing season governs its rapid flowering.

The plant is a small annual or short-lived herb with slender, simple to branched stems arising from a thin taproot. The leaves are entire to slightly toothed, oblanceolate to spathulate and mostly basal. The inflorescence is a lax, ebracteate raceme bearing minute, inconspicuous flowers with four whitish petals scarcely exceeding the sepals, giving the species its epithet. The fruit is a small, linear, terete to slightly compressed silique that is sessile or shortly stipitate, dehiscing to release tiny seeds arranged in a single row per locule.

The genus Ianhedgea was segregated by Al-Shehbaz and O'Kane and named in honour of the cruciferologist Ian Charleson Hedge; the species was formerly placed in Sisymbrium and related genera, its basionym attributed to Hooker f. and Thomson. The transfer reflects molecular and morphological reassessment of the tribe Sisymbrieae. As an inconspicuous, widespread high-mountain annual, it faces no recognised conservation threat but is poorly documented owing to its small size and remote habitat.

Author: (Hook.f. & Thomson) Al-Shehbaz & O'Kane · Sources: POWO (Kew), Flora of Pakistan, Annotated Checklist of the Flowering Plants of Nepal, GBIF, Al-Shehbaz: Cruciferae systematics

Aquifoliaceae

Ilex excelsa var. hypotricha

by G & P Jürgens

(Loes.) S.Y. Hu

Bhutan2015 536
Bhutan Mo-Chu 1300m, October
Bhutan2015 540
Bhutan Mo-Chu 1300m, October

Description

Ilex excelsa var. hypotricha is a holly of the eastern Himalaya and adjacent China, distributed through Bhutan, Nepal, NE India, Bangladesh and SW China as recorded by GBIF (CN, IN, NP, BD) on the basis of about 39 occurrences. The photographed tree was found in western Bhutan along the Mo-Chu at about 1,300 m in October. It is a component of subtropical and warm-temperate broadleaf forest, growing on humid hill slopes, along streams and forest margins, generally between about 1,000 and 2,200 m, where it occurs as an understorey to mid-canopy evergreen tree in mixed laurophyllous woodland.

It is an evergreen tree or large shrub with smooth grey bark and glabrous to finely puberulent young shoots. The leaves are alternate, leathery, elliptic to oblong-lanceolate, with an entire to remotely crenulate margin and an acuminate apex; this variety is distinguished by a thin pubescence on the lower surface, particularly along the midrib, the feature signalled by the epithet hypotricha. As in all Ilex the plants are dioecious, the small four-merous white to greenish flowers borne in axillary fascicles or short cymes, the staminate and pistillate flowers on separate trees. The fruit is a small globose red drupe containing several hard pyrenes (stones), characteristically ornamented as is diagnostic in the genus.

The genus Ilex is large and taxonomically intricate, with infraspecific variation in leaf indumentum often used to delimit varieties such as this one; the bony pyrene sculpturing remains an important systematic character. As a forest tree of moderately wide range, this taxon is not regarded as threatened, though its dependence on intact mid-elevation broadleaf forest links its fortunes to the conservation of eastern Himalayan woodland.

Author: (Loes.) S.Y. Hu · Sources: POWO (Kew), Flora of China Vol. 11, Flora of Bhutan Vol. 2, GBIF, Loesener: Monographia Aquifoliacearum

Schisandraceae

Illicium griffithii

by G & P Jürgens

Hook.f. & Thomson

Bhutan2012 346
Bhutan Dochu-La 3000m, September

Description

Illicium griffithii Hook.f. & Thomson is an aromatic evergreen tree or shrub of the eastern Himalaya and montane Southeast Asia. GBIF records it from Bhutan, NE India, China, Myanmar, Bangladesh, Vietnam, Cambodia and Malaysia (about 220 occurrences), a distribution centred on the wet temperate to subtropical forests of the eastern Sino-Himalaya. It grows in cool, humid, mossy broad-leaved and mixed conifer forest, often as an understorey component on damp slopes and ridges, typically between roughly 1,800 and 3,000 m; the illustrated plant is from Bhutan at Dochu-La, 3,000 m, in September, near the upper limit of its range.

The plant is a small to medium-sized tree with smooth bark and aromatic tissues. The leaves are alternate but crowded toward the branch tips in pseudowhorls, simple, entire, elliptic to oblanceolate, leathery, glabrous and gland-dotted, exuding an anise-like scent when crushed. The flowers are solitary and axillary, with numerous spirally arranged perianth segments grading from sepaloid to petaloid, pinkish to dark red, the stamens and free carpels also numerous in the manner of the basal angiosperms. The fruit is the characteristic star-shaped aggregate of (usually) 8–13 woody follicles arranged in a single whorl, each follicle opening to release a single glossy seed.

Illicium (Schisandraceae, formerly Illiciaceae) belongs to the basal angiosperm order Austrobaileyales. Like its relatives the seeds and fruit contain toxic sesquiterpene lactones (anisatin-type), and the star anise of this species is harvested locally for incense, flavouring and medicine, demanding care given its toxicity. The species is widespread within suitable montane forest and is not currently regarded as threatened.

Author: Hook.f. & Thomson · Sources: POWO (Kew), GBIF, Flora of China Vol. 7, Flora of Bhutan Vol. 1, Smith: A Taxonomic Review of Illicium (Sargentia)