Author

G & P Jürgens

Rubiaceae

Ophiorrhiza treutleri

by G & P Jürgens

Hook.f.

Sikkim 2006 451 ergebnis
Sikkim 2006 450 ergebnis
India West-Bengal, Tolung 2200m, May

Description

Ophiorrhiza treutleri is an eastern Himalayan understorey herb confined to India, Nepal and Bhutan, documented by roughly 39 georeferenced records that cluster in the moist mid-montane forests of the region. It is a plant of shaded, humid habitats, growing on the floor of dense evergreen and mixed broadleaved forest, along streamsides, mossy banks and damp ravines where atmospheric humidity remains high throughout the year. The specimen photographed at Tolung in West Bengal (India) at about 2200 m in May reflects its typical occurrence in the cool, perpetually damp montane belt, where it flowers in spring beneath a closed canopy.

It is a small perennial or weakly suffrutescent herb with slender, often decumbent stems that root at the lower nodes and bear a sparse indumentum. The leaves are opposite, ovate to elliptic-lanceolate, acuminate at the apex and somewhat asymmetric at the base, with conspicuous lateral venation and small interpetiolar stipules characteristic of the family. The inflorescence is a terminal, scorpioid cyme; the flowers are small, white to pinkish and tubular, with a five-lobed corolla and an inferior bilocular ovary. As in many Ophiorrhiza, the species is distylous, producing pin and thrum flowers. The fruit is a characteristically broad, didymous (two-lobed) capsule that dehisces loculicidally to release numerous minute angular seeds.

Ophiorrhiza belongs to the tribe Ophiorrhizeae of the Rubiaceae and is notable for the accumulation of camptothecin and related alkaloids, which has drawn pharmacological interest to several species. The heterostyly of O. treutleri promotes outcrossing through insect-mediated pollination, while its capsular fruits are adapted to rain-splash and gravity dispersal in the still air of the forest floor. As an obligate shade species tied to undisturbed montane forest, it is vulnerable to canopy opening, and its conservation is effectively linked to the protection of intact eastern Himalayan woodland.

Author: Hook.f. · Sources: POWO (Kew), GBIF, Flora of China Vol. 19, Flora of Bhutan Vol. 2, Flora of Nepal, Deb & Mondal Revision of the Genus Ophiorrhiza (Rubiaceae)

Cactaceae

Opuntia monacantha

by G & P Jürgens

(Willd.) Haw.

Bhutan2014 693
Bhutan Pele-La 2800m, May

Description

Opuntia monacantha is a prickly-pear cactus native to subtropical South America (Brazil, Argentina, Uruguay and Paraguay) that has become one of the most widely naturalised Opuntia species in the world. Its 4754 GBIF occurrences span Australia, South Africa, the Mediterranean, East Africa, India, China, Nepal, Bhutan and many other regions, almost all representing introduced and frequently invasive populations. In the Himalaya it persists as an escape from cultivation on dry, sunny, rocky slopes, banks, walls and disturbed ground in warm valleys. The record from the Pele-La area of Bhutan at about 2800 m in May is notable as a relatively high-elevation occurrence, the plant having been spread through cultivation as a hedge and ornamental into the inner dry valleys of the eastern Himalaya.

It is a succulent shrub to small tree, sometimes developing a distinct cylindrical woody trunk, with a branched crown of flattened green photosynthetic stem-segments (cladodes or pads). The pads are obovate to oblong, glossy green and somewhat flaccid, bearing areoles that produce tufts of minute barbed glochids and usually one or few (occasionally none) stout spines, the sparse armature giving rise to the epithet monacantha. The leaves are reduced to tiny caducous scales. The flowers are large, solitary, sessile on the pad margin, with a rotate perianth of bright yellow tepals often reddish at the base and numerous stamens. The fruit is a fleshy, obovoid, reddish-purple berry, frequently proliferous, the pulp edible and the seeds dispersed by frugivores.

The genus Opuntia is among the most successful of invasive plant lineages, the readily detached, root-forming cladodes enabling vigorous vegetative spread, while the bird- and mammal-dispersed fruits extend its reach. O. monacantha is regarded as a noxious weed in several countries and has been a target of biological control using cochineal insects. In the Himalayan context it is an introduced naturalised alien rather than a native element; its conservation status is irrelevant in the usual sense, the concern instead being its potential to colonise and degrade dry montane slopes.

Author: (Willd.) Haw. · Sources: POWO (Kew), GBIF, Flora of China Vol. 13, Flora of Pakistan, Flora of Nepal, Anderson The Cactus Family

Asteraceae

Oreoseris gossypina

by G & P Jürgens

(Royle) X.D.Xu & V.A.Funk

Garw 2005 419 ergebnis
India Garhwal Didina 2470m, September
Garh 07 70 ergebnis
India Garhwal Nanu Mandakini 2300m, June

Description

Oreoseris gossypina is a rosette-forming perennial herb of the temperate and subalpine Himalaya, recorded from Pakistan, India, Nepal, China and Bhutan across more than 300 occurrences. It typically inhabits open grassy slopes, rocky banks and forest margins, often on disturbed or grazed ground, at elevations of roughly 1800 to 3500 m. The documented collections derive from Garhwal in India, at Didina (2470 m, September) and the Nanu Mandakini valley (2300 m, June), the two dates spanning much of its long flowering and fruiting season in the Western Himalaya.

The plant produces a basal rosette of obovate to oblanceolate leaves that are conspicuously white-woolly beneath, the dense cottony indumentum giving rise to the epithet gossypina. The leaf margins are sinuate-dentate and the lamina narrows into a winged petiole. Solitary capitula are borne on slender, bracteate scapes; each head is heterogamous and radiate, with an involucre of imbricate, often arachnoid-hairy phyllaries. The marginal ray florets are ligulate and pale, the disc florets tubular; the achenes are ribbed and surmounted by a pappus of barbellate bristles aiding wind dispersal.

The species was long placed in Gerbera and is also encountered under Leibnitzia; its current placement in Oreoseris (Mutisieae) reflects molecular and morphological revision by X.D. Xu and V.A. Funk. As a member of an early-diverging composite lineage it is of phylogenetic interest, and its mutisioid floral structure attracts a range of pollinating insects. The species is widespread and faces no recognised threat.

Author: (Royle) X.D.Xu & V.A.Funk · Sources: POWO (Kew), GBIF, Flora of China, Flora of Pakistan, Annotated Checklist of the Flowering Plants of Nepal, Xu & Funk revision of Mutisieae

Bignoniaceae

Oroxylum indicum

by G & P Jürgens

(L.) Kurz

Bhutan2012 969
Bhutan Trithangebe 900m, October
Bhutan2015 103
Bhutan Galephug 500m, October

Description

Oroxylum indicum, the Indian trumpet tree or midnight horror, is a small deciduous tree of subtropical and tropical Asia, ranging from India, Nepal and Bhutan through Bangladesh, Myanmar and southern China to Indochina, Thailand, Sri Lanka and across Malesia to the Philippines. GBIF aggregates around 1440 occurrences. It is a tree of forest margins, secondary growth, ravines and roadsides at low to moderate elevations, often in seasonally dry monsoon forest. The Bhutanese specimens at Trithangebe (900 m) and Galephug (500 m) in October occupy this warm foothill zone, fruiting at the close of the monsoon when the great pendulous pods become conspicuous.

The tree has a sparse crown and stout, soft-wooded branches marked with prominent leaf scars. Its leaves are very large, opposite and two- to three-pinnate, often a metre or more across, with ovate, acuminate leaflets, the falling rachides littering the ground beneath. The flowers open at night in a long erect terminal raceme, each large, fleshy and campanulate, lurid reddish-purple outside and paler within, malodorous and bat-pollinated. Most striking is the fruit: a flattened, sword-shaped, sabre-like capsule up to a metre long that splits into two woody valves to release numerous flat seeds broadly winged with a papery membrane for wind dispersal.

A member of Bignoniaceae, Oroxylum is a distinctive near-monotypic genus set apart by its enormous pinnate leaves, nocturnal chiropterophilous flowers and giant samaroid pods. The species is of considerable ethnobotanical importance: its bark, seeds and young fruit are widely used in Ayurvedic and traditional medicine, and the tender pods are eaten as a vegetable. Despite localised harvesting it remains common and widespread, and is not regarded as globally threatened.

Author: (L.) Kurz · Sources: POWO (Kew), GBIF, Flora of China Vol. 18, Flora of Bhutan Vol. 2, Annotated Checklist of the Flowering Plants of Nepal, Gentry monograph of Bignoniaceae

Poaceae

Oryza sativa

by G & P Jürgens

L.

Bhutan2015 559
Bhutan Moshu 1700m, October

Description

Oryza sativa, Asian cultivated rice, is the world's most important cereal staple and is grown across the warm-temperate to tropical zones of every inhabited continent. Domesticated in Asia from wild progenitors such as O. rufipogon, it is documented in GBIF by more than four hundred thousand occurrences spanning India, China, Southeast Asia, the Americas, Africa, Europe and beyond, reflecting both its agricultural ubiquity and intensive germplasm collection. It is essentially never truly wild but rather a cultigen of flooded paddies, irrigated terraces and seasonally inundated fields, with weedy and feral forms persisting around cultivation. The plant photographed at Moshu in Bhutan at 1700 m in October represents the terraced mid-montane rice cultivation characteristic of the Bhutanese Himalaya, where hardy, often red-grained landraces are grown well above the typical lowland range and are harvested as the autumn paddies ripen to gold.

The plant is an annual (occasionally short-lived perennial) grass forming erect tufts of hollow, jointed culms typically 0.5 to 1.5 m tall, rooting at the lower nodes and tolerant of standing water. The leaves are linear, flat and scabrous, with a long membranous ligule and well-developed auricles at the junction of sheath and blade. The inflorescence is a terminal, much-branched, nodding panicle bearing numerous laterally compressed spikelets, each reduced to a single fertile floret subtended by two small sterile lemmas; the fertile lemma is keeled and may be awned or awnless. Six stamens and a feathery, two-branched stigma effect predominantly self-pollination, and the fruit is the familiar caryopsis (grain), enclosed by the persistent lemma and palea as the husk.

Oryza belongs to the grass family Poaceae, tribe Oryzeae, a lineage of marsh-adapted grasses. As a domesticate, O. sativa encompasses immense genetic diversity organised principally into the indica and japonica subspecies groups, together comprising tens of thousands of landraces and modern cultivars adapted to environments from deepwater floodplains to upland terraces. Bhutanese and Himalayan rice agriculture, often involving cold-tolerant high-altitude landraces, is of particular interest for crop genetic conservation. The species is of no conservation concern itself, but the in-situ and ex-situ preservation of its traditional landraces and of wild Oryza relatives is a recognised priority for global food security.

Author: L. · Sources: POWO (Kew), GBIF, Flora of China Vol. 22, Flora of Bhutan Vol. 3 Part 2, Flora of Nepal, Flora of Pakistan, Wild and Cultivated Rices (Oryza): a Taxonomic Treatment (T.T. Chang; Vaughan, The Wild Relatives of Rice)

Melastomataceae

Osbeckia capitata

by G & P Jürgens

Benth. ex Naudin

Bhutan2012 538
Bhutan Wangdi 2600m, September
Bhutan2012 539
Bhutan Wangdi 2600m, September

Description

Osbeckia capitata Benth. ex Naudin is a subshrubby herb of the eastern Himalaya, recorded by GBIF (69 occurrences) from China, India, Bhutan and Bangladesh. It occupies open grassy slopes, forest clearings, scrub margins and disturbed banks in the subtropical to lower temperate hill zone, flowering through the late monsoon. The photographed plant from Wangdue Phodrang (Wangdi) in western Bhutan at 2600 m in September is characteristic of its occurrence on warm, humid mid-elevation slopes among grasses and low shrubs.

The plant is an erect to ascending perennial herb with quadrangular, bristly stems bearing opposite, sessile to shortly petiolate leaves. The blades are ovate to lanceolate, setose on both surfaces, with the strongly arcuate three-to-five longitudinal nerves diagnostic of the family. As the epithet capitata indicates, the flowers are aggregated into dense terminal heads or capitate clusters; each flower has four pink to purple petals, a setose, urceolate hypanthium, and the typical melastomataceous androecium of curved stamens whose elongate, beaked anthers open by apical pores. The fruit is a setose urceolate capsule retained within the persistent hypanthium.

Osbeckia is a palaeotropical genus of around 50 species best developed in tropical Asia, separated from Melastoma by its smaller, dry, poricidal-anthered flowers and capsular fruits; the capitate inflorescence distinguishes O. capitata within the Himalayan members. The poricidal anthers are adapted to buzz-pollination by bees, and several congeners have local medicinal use. The species is not assessed as threatened, persisting in open and lightly disturbed montane habitats across its eastern Himalayan range.

Author: Benth. ex Naudin · Sources: POWO (Kew), GBIF, Flora of Bhutan, Flora of China, Melastomataceae of the Indian Subcontinent, Hansen monograph on Osbeckia

Melastomataceae

Osbeckia nutans

by G & P Jürgens

Wall.

Bhutan2015 71
Bhutan Wangdi Phodrang 1700m, October
Bhutan2012 422
Bhutan Wangdi 2700m, September

Description

Osbeckia nutans Wall. is a subshrubby herb of the eastern Himalaya and adjoining Southeast Asia, recorded by GBIF (71 occurrences) from India, Nepal, Bhutan, Myanmar and Vietnam. It is a plant of open hillsides, grassy banks, forest clearings and roadside scrub in the subtropical to lower temperate zone, flowering chiefly in the autumn months. The cited Bhutanese material, gathered near Wangdue Phodrang at 1700 m in October and at 2700 m in September, illustrates its tolerance of a fairly wide altitudinal span on the warm, humid southern slopes where it colonises disturbed and seasonally moist ground.

The plant is an erect to ascending perennial with quadrangular, often setose stems bearing opposite, sessile to subsessile leaves. The leaf blades are lanceolate to ovate-lanceolate with the characteristic melastomataceous three-to-five strongly arcuate longitudinal nerves, and the surfaces are clothed in stiff appressed bristles. As the epithet nutans implies, the flowers or buds are inclined to nodding; the showy pink to purplish blooms have four petals, a setose, urceolate hypanthium, and the typical Melastomataceae androecium of geniculate stamens with elongate, beaked anthers opening by terminal pores. The fruit is a setose, urceolate capsule enclosed in the persistent hypanthium.

Osbeckia is a palaeotropical genus of around 50 species centred on tropical Asia, distinguished from the related Melastoma by its smaller, dry, pore-opening capsules. Its poricidal anthers are adapted to buzz-pollination by bees. Several Osbeckia species have ethnomedicinal uses in the region. Osbeckia nutans is locally frequent and not regarded as threatened, persisting well in open and lightly disturbed habitats.

Author: Wall. · Sources: POWO (Kew), GBIF, Flora of Bhutan, Flora of China, Melastomataceae of the Indian Subcontinent, Hansen monograph on Osbeckia

Melastomataceae

Osbeckia stellata

by G & P Jürgens

Buch.-Ham. ex D.Don

Bhutan2012 530
Bhutan Tserang 1300m, September
Bhutan2012 660
Bhutan Tserang 1600m, September
Bhutan2015 206
Bhutan Zhemgang 1000m, October
Bhutan2015 207
Bhutan Zhemgang 1000m, October

Description

Osbeckia stellata Buch.-Ham. ex D.Don is a shrub of the melastome family ranging across the Himalaya and tropical Asia, recorded from China, India, Nepal, Bhutan, Myanmar, Thailand, Vietnam, Malaysia and Laos, with about 704 GBIF occurrences. It grows on open hillsides, forest margins, scrub, grassy banks and disturbed slopes in the subtropical and warm-temperate belt, generally between about 900 and 2000 m. It was recorded in Bhutan at Tserang at 1300 and 1600 m and at Zhemgang around 1000 m, flowering in September and October, when its conspicuous magenta blooms colour the autumn hill vegetation of the outer ranges.

It is an erect, branched shrub with quadrangular, often reddish stems bearing appressed, bristly stellate or strigose hairs. The leaves are opposite, ovate-lanceolate, entire, and conspicuously three- to five-nerved with the characteristic curved-convergent venation of Melastomataceae, both surfaces rough with stiff hairs. The flowers are large and showy, borne in terminal cymose clusters; the four broad obovate petals are rose-purple to magenta, surrounding eight stamens with distinctively geniculate, beaked anthers, set on an urceolate hypanthium clothed in branched, stellate-tipped bristles. The fruit is an urn-shaped capsule enclosed by the persistent bristly hypanthium, releasing numerous minute cochleate seeds.

Osbeckia is distinguished from the related Melastoma by its smaller seeds and capsular fruit, and O. stellata is among the most ornamental and widespread Himalayan species, sometimes grown for its vivid flowers. Its poricidal anthers are buzz-pollinated by bees, while the small seeds are dispersed from the dry capsules. Common in disturbed and secondary habitats, it readily colonises cleared ground and is of no conservation concern.

Author: Buch.-Ham. ex D.Don · Sources: POWO (Kew), GBIF, Flora of China, Flora of Bhutan, Flora of British India, Melastomataceae monograph (Hansen revision of Osbeckia)

Euphorbiaceae

Ostodes paniculata

by G & P Jürgens

Blume

Bhutan2015 194
Bhutan Zhemgang 1000m, October
Bhutan2015 195
Bhutan Zhemgang 1000m, October

Description

Ostodes paniculata is a tree or large shrub widely distributed through tropical and subtropical Asia, recorded by GBIF from China, Indonesia, Thailand, India, Myanmar, Vietnam, Nepal, Bhutan, Laos, Cambodia, Malaysia and Korea across more than 1100 occurrences. It is a component of evergreen and semi-evergreen broad-leaved forest in warm, humid lowland and lower montane settings, usually below about 1500 m, often on hillslopes and in valley forest. The photographed individual from Zhemgang in southern Bhutan at about 1000 m, in October, reflects this warm-temperate to subtropical foothill habitat where the species reaches the northern margin of its range along the Himalayan front.

The plant is a monoecious, evergreen tree with smooth bark and a milky or watery exudate. The leaves are alternate, simple, broadly elliptic to ovate, long-petiolate with a pair of glands at the petiole apex, the margin serrate to glandular-toothed and the base often with a few prominent basal nerves. The inflorescences are terminal panicles bearing numerous small white to creamy flowers, the staminate and pistillate flowers separate, with five petals and conspicuous disk glands; staminate flowers have numerous stamens. The fruit is a globose, three-locular capsule, somewhat woody, that splits septicidally to release the large smooth seeds.

Ostodes is a small genus of the Euphorbiaceae (subfamily Crotonoideae) centred on tropical Asia, and O. paniculata is its most widespread and well-known species, valued locally for its timber and seed oil. Its broad range and tolerance of secondary forest mean it is not of conservation concern, and it is frequent across much of Indo-Malaya. Phytogeographically it exemplifies the Indo-Malayan element that penetrates the Himalaya through the warm, wet foothill forests of Bhutan and northeast India.

Author: Blume · Sources: POWO (Kew), GBIF, Flora of China, Flora of Bhutan, Flora of Thailand, Radcliffe-Smith Euphorbiaceae treatments

Santalaceae

Osyris lanceolata

by G & P Jürgens

Hochst. & Steud.

Bhutan2014 151
Bhutan Trashigang 1700m, May

Description

Osyris lanceolata, the East African sandalwood, is a remarkably wide-ranging evergreen shrub spanning the Mediterranean basin, much of Africa and southern Asia; its roughly 4217 GBIF records reach from Spain, Portugal and Morocco through eastern and southern Africa (Kenya, Tanzania, Ethiopia, South Africa, Zimbabwe, Namibia, Angola) to India, Sri Lanka, Nepal, China and Bhutan. In the eastern Himalaya it occupies warm, dry montane slopes, as recorded near Trashigang in eastern Bhutan at about 1700 m in May. It favours open woodland, scrub and rocky hillsides on well-drained soils, persisting as a hardy, drought-tolerant component of seasonally dry vegetation.

The plant is a glabrous, much-branched shrub or small tree with slender, angular green twigs and alternate, leathery leaves that are narrowly lanceolate to elliptic, sometimes reduced and scale-like. Like other Santalaceae it is a hemiparasite, attaching by root haustoria to neighbouring plants while retaining green, photosynthetic foliage. The species is dioecious, bearing small, greenish-yellow flowers in axillary clusters on separate plants; the inferior ovary develops into a small, globose, fleshy drupe ripening red to blackish and dispersed by birds.

Osyris belongs to the sandalwood family, and O. lanceolata is exploited as a substitute for true sandalwood, its aromatic, oil-rich heartwood harvested for fragrant oil, carvings and incense. This demand has driven heavy, often illegal exploitation, particularly in East Africa, causing severe population declines and the listing of its populations under CITES Appendix II. The Himalayan populations form part of this broad, biogeographically intriguing range.

Author: Hochst. & Steud. · Sources: POWO (Kew), GBIF, Flora of China Vol. 5, Flora of Bhutan Vol. 1, Flora of Nepal, Flora of Tropical East Africa (Santalaceae)