Tag:

Bhutan

Flowers of Bhutan — 1326 plant species documented across the Bhutanese Himalaya, from dense broadleaf and conifer forests to alpine scrub and meadows. Bhutan’s largely intact wilderness shelters an exceptional diversity of orchids, rhododendrons, primulas and Himalayan poppies, many of them regional endemics. Each species page includes a botanical description, distribution, habitat and flowering time, with the original photograph and its recorded altitude and locality.

Fabaceae

Astragalus concretus

by GP Jürgens

Benth.

Bhutan2012 349
Bhutan Wangdi 2000m, September
Sikkim 2006 466 ergebnis
India West-Bengal, Ruhig-Chu 2100m, May

Description

Astragalus concretus is a Himalayan milkvetch recorded from Nepal, India, China, Pakistan and Bhutan, with about 147 georeferenced occurrences concentrated along the central and eastern ranges; scattered records from the United States, Russia and Belgium derive from herbarium and database holdings rather than wild populations. It favours open, sunny banks, dry slopes, scrub margins and disturbed ground in the subtropical to lower temperate zone, broadly between 1500 and 2500 m. The cited gatherings from Wangdue in Bhutan at 2000 m in September and from the Rishi Chu valley in West Bengal at 2100 m in May indicate a tolerance of warm mid-elevation habitats.

It is a perennial or robust herb with ascending to spreading stems. The leaves are imparipinnate with several pairs of oblong to elliptic leaflets, the foliage typically appressed-pubescent. The flowers are borne in axillary racemes; the papilionaceous corolla, of purplish to pale colouring, shows the standard, wing and keel petals characteristic of the genus, subtended by a campanulate, toothed calyx. The fruit is a legume pod, in this species somewhat inflated and incompletely two-celled by intrusion of the ventral suture, the feature reflected in the epithet.

Astragalus is among the largest of all plant genera, and its Himalayan members are taxonomically intricate, separated largely on pod and indumentum characters. As a nitrogen-fixing legume, A. concretus contributes to soil enrichment on poor, eroding slopes. It is not regarded as threatened, occurring widely across disturbed and natural openings throughout its range.

Author: Benth. · Sources: POWO (Kew), GBIF, Flora of China, Flora of Bhutan, Astragalus and Oxytropis monographs of Podlech and Maassoumi

Fabaceae

Astragalus sikkimensis

by G & P Jürgens

Benth. ex. Bunge

9F417E3DE29B4FE4ABBB6A304481347F
Bhutan Tsochenchen, 3550m June

Description

Astragalus sikkimensis is a Himalayan milkvetch recorded from India, Nepal, Bhutan and China, with about 68 GBIF occurrences distributed across the central and eastern range. It is a plant of open alpine and subalpine slopes, stony pastures and grassy meadows, typically growing between roughly 3000 and 4500 m. The photographed plant at Tsochenchen in Bhutan at 3550 m, flowering in June, reflects its early-summer anthesis at the onset of the growing season, when it occupies well-drained, often gravelly turf in the cool, exposed conditions of the high meadows above the forest line.

The species is a perennial herb arising from a woody rootstock, with stems that are decumbent to shortly ascending and an indumentum of fine appressed hairs. The leaves are imparipinnate, composed of several pairs of small elliptic to oblong leaflets, with persistent stipules at the base of the petioles. The flowers are borne in short axillary racemes or head-like clusters and are typically pink-purple to violet, with the standard, wing and keel petals of the papilionaceous corolla and a tubular, hairy calyx with triangular teeth. The fruit is a small legume (pod), often somewhat inflated and enclosed within or shortly exceeding the persistent calyx, splitting to release the seeds.

Astragalus is one of the largest of all plant genera, and its Himalayan alpine representatives such as A. sikkimensis form symbiotic root nodules with nitrogen-fixing rhizobia, an asset in nutrient-poor high-altitude soils. The papilionaceous flowers are bee-pollinated. The species is reasonably widespread within its montane band and is not regarded as threatened, though its alpine pastures are subject to grazing pressure across the inhabited Himalayan ranges.

Author: Benth. ex. Bunge · Sources: POWO (Kew), GBIF, Flora of Bhutan, Flora of China (Fabaceae), Podlech & Zarre Taxonomic Revision of Astragalus

Fabaceae

Astragalus stipulatus

by GP Jürgens

D.Don ex. Sims

BhutanPG2011 849
Bhutan Paro-Chu, 2400m July

Description

Astragalus stipulatus is a Himalayan milk-vetch distributed across Nepal, India, China and Bhutan, with around 83 GBIF occurrences. It is a plant of open, sunny situations in the temperate to lower subalpine zone, occupying dry grassy slopes, rocky banks, riverside terraces and disturbed ground, generally between about 2000 and 3500 m. The plant illustrated from the Paro Chu valley in Bhutan at 2400 m, flowering in July, is typical of its occurrence along well-drained, gravelly valley sides during the monsoon season.

It is a perennial or sometimes biennial herb with ascending to spreading, often somewhat straggling stems arising from a branched rootstock. The leaves are imparipinnate with several pairs of small elliptic to oblong leaflets and conspicuous, often connate stipules that give the species its epithet. The pea-like flowers are borne in axillary racemes; the papilionaceous corolla is purplish to pale violet or whitish, with the standard exceeding the wings and keel, and the calyx is tubular-campanulate with subequal teeth. The fruit is an oblong, often somewhat curved and inflated legume that may be bilocular through intrusion of the lower suture.

Astragalus, the largest genus of flowering plants, is richly represented in the Himalaya and Central Asia. A. stipulatus (D. Don ex Sims) belongs to the diverse Himalayan assemblage of the genus; it is widespread and of no conservation concern, contributing to early-successional and grazing-disturbed communities and, as a legume, to soil nitrogen enrichment through root nodulation.

Author: D.Don ex. Sims · Sources: POWO (Kew), GBIF, Flora of Bhutan, Flora of China, Podlech & Zarre monograph of Old World Astragalus

Campanulaceae

Asyneuma fulgens

by GP Jürgens

(Wall.) Briq.

BhutanPG2011 840
Bhutan Paro-Chu, 2400m July

Description

Asyneuma fulgens is a bellflower-family herb widely distributed across the Himalaya and adjacent Asia, well represented in GBIF with about 276 occurrences from China, India, Nepal, Bhutan, Myanmar and beyond. It is a plant of open, sunny situations, occurring on grassy and rocky slopes, banks, clearings, scrub and roadside verges in the warm-temperate to lower subalpine belt. The plant photographed along the Paro-Chu in Bhutan at about 2400 m in July was recorded in the monsoon flowering season, consistent with its preference for moist but well-drained montane slopes in the lower part of its altitudinal range.

It is an erect perennial herb, often slender and somewhat wiry, with simple or sparingly branched stems arising from a thickened rootstock and exuding latex when cut, as is typical of the family. The leaves are alternate, the lower ones petiolate and ovate to lanceolate, the upper sessile and narrower, with toothed margins. The flowers are borne in elongate, often interrupted spike-like or racemose inflorescences; each has a five-lobed calyx and a deeply five-parted, star-shaped corolla in shades of blue, violet or purple, the linear lobes spreading at anthesis. The style is exserted with a lobed stigma, and the fruit is a capsule dehiscing by lateral pores to shed many small seeds.

Asyneuma is segregated from Phyteuma and Campanula chiefly by its deeply divided, rotate corolla and the manner of capsule dehiscence. The genus is centred on Eurasia, with a notable Himalayan and Sino-Himalayan representation. As a widespread, ecologically tolerant species occupying disturbed as well as natural slopes, A. fulgens is not of conservation concern, and it provides a nectar and pollen resource for bees and other insect visitors in montane meadows.

Author: (Wall.) Briq. · Sources: POWO (Kew), GBIF, Flora of China, Flora of Bhutan, Hooker Flora of British India, Lammers World Checklist of Campanulaceae

Euphorbiaceae

Baliospermum calycinum

by GP Jürgens

Müll.Arg.

Bhutan2012 684
Bhutan Tserang 850m, September

Description

Baliospermum calycinum is a broadly distributed spurge of the Indo-Himalayan and Southeast Asian region, with more than 550 georeferenced occurrences across China, Thailand, India, Myanmar, Nepal, Vietnam, Bhutan, Laos and Bangladesh. It is a plant of warm, subtropical forest margins, scrub, ravines and disturbed ground at low to moderate elevations. The specimen recorded near Tsirang (Tserang) in southern Bhutan at about 850 m in September reflects its typical lowland habitat, fruiting toward the end of the monsoon on moist, fertile soils in partly shaded settings.

It is a monoecious, somewhat woody undershrub or robust herb exuding a watery to milky sap typical of the Euphorbiaceae. The leaves are alternate, large, the lower ones often broadly ovate and palmately lobed while the upper become narrower and merely toothed, with glandular teeth and a serrate margin. The small, apetalous unisexual flowers are borne in axillary racemiform inflorescences, with female flowers below and numerous male flowers above; the species is distinguished by its conspicuously developed, persistent calyx. The fruit is a three-lobed schizocarpic capsule splitting into three two-valved cocci that eject the smooth, mottled seeds.

Within Euphorbiaceae the genus Baliospermum comprises a small number of Asian species long valued in traditional medicine for the purgative and irritant properties of the seed oil. Taxonomic confusion with related taxa such as B. montanum has historically obscured its limits, and modern treatments rely on calyx, leaf-lobing and capsule characters for separation. Common and weedy across its wide range, it is of least conservation concern.

Author: Müll.Arg. · Sources: POWO (Kew), GBIF, Flora of Bhutan, Flora of China, Flora of British India, Radcliffe-Smith's account of Euphorbiaceae

Acanthaceae

Barleria cristata

by G & P Jürgens

L.

Bhutan2012 1062
Bhutan Koma-Chu-Valley 800m, September
Bhutan2015 173 scaled
Bhutan Zhemgang 910m, October

Description

Barleria cristata is a widespread species distributed from the Indian subcontinent through Southeast Asia to southern China, occurring in India, Nepal, Bhutan, Pakistan, Myanmar, Thailand, and Laos. It has also become naturalized in parts of the tropics worldwide, including Australia, Brazil, and the Philippines. The species inhabits open and disturbed forests, rocky slopes, stream banks, and forest margins at elevations from near sea level to approximately 1,800 m. In Bhutan, it is found in the warm broadleaved forests of the southern foothills, as documented from the Koma-Chu Valley at 800 m and near Zhemgang at 910 m, where it flowers from September to October.
The plant is an erect to spreading shrub or subshrub, 0.5–1.5 m tall, with quadrangular stems that are pubescent when young. Leaves are opposite, ovate to elliptic, 5–12 cm long, with an acuminate apex and entire margins, bearing scattered hairs on both surfaces. The inflorescence is a dense, terminal or axillary spike, subtended by conspicuous, ovate, spinose-tipped bracts that give the species its epithet "cristata" (crested). Flowers are bilabiate, 3–4 cm long, typically violet to pale blue or occasionally white. The calyx is deeply four-lobed with two larger outer lobes and two smaller inner ones. The fruit is an oblong capsule containing two to four flattened, hygroscopic seeds that are explosively dehiscent when wetted.
Barleria is a large pantropical genus of approximately 300 species, with its centre of diversity in Africa and Asia. B. cristata is among the most commonly cultivated ornamental species in the genus and has escaped cultivation in numerous tropical regions, raising concerns about its invasive potential in some areas. Ecologically, it provides nectar resources for butterflies and long-tongued pollinators. The species exhibits considerable variation in flower colour across its range, which has led to the description of several infraspecific taxa, though most are not currently recognized.

Author: L. · Sources: POWO (Kew), GBIF, Flora of Bhutan Vol. 2, Flora of China Vol. 19

Fabaceae

Bauhinia purpurea

by GP Jürgens

L.

Bhutan2015 551
Bhutan Punaka 1400m, October
Nepal 95 20 P29 ergebnis
Nepal Gorkha 1200m, Octobre

Description

Bauhinia purpurea is a tropical and subtropical tree native to South and Southeast Asia, with a centre of diversity across India, Nepal, Bhutan, southern China, Thailand, Malaysia and the Philippines. Through widespread cultivation as an ornamental and street tree it has become naturalised across the tropics, and the more than 11,500 GBIF records include numerous occurrences in the Americas (Brazil, Colombia, Mexico, Costa Rica, the Caribbean) and elsewhere. In its native Himalayan foothill range it occupies warm broad-leaved forest, scrub and cultivated margins at low to mid elevations; the Bhutanese tree at Punakha (1400 m) and the Nepalese population near Gorkha (1200 m), both flowering in October, mark its autumn blooming in the eastern Himalaya.

It is a small to medium-sized deciduous tree with a spreading crown. The leaves are distinctive and diagnostic of the genus: broadly ovate to orbicular, cleft at the apex into two rounded lobes for up to one-third to one-half their length, giving the characteristic bilobed "camel-foot" outline, with several palmate veins. The fragrant flowers are borne in short racemes and have five free, narrow, clawed petals coloured rose-purple to magenta, with usually three fertile stamens. The fruit is a flattened, linear-oblong, woody legume that dehisces elastically to scatter several seeds.

Bauhinia purpurea is often confused with the closely allied B. variegata, from which it differs in its narrower petals, reduced number of fertile stamens and later flowering season. The species is economically and culturally significant, valued for shade, ornament, edible flower buds, fibre and traditional medicine. It is common and widely planted, of no conservation concern, but its readiness to naturalise has led to its being treated as locally invasive in some introduced tropical regions.

Author: L. · Sources: POWO (Kew), GBIF, Flora of China, Flora of Bhutan, Annotated Checklist of the Flowering Plants of Nepal, Larsen & Larsen revision of Asian Bauhinia (monograph)

Fabaceae

Bauhinia variegata

by GP Jürgens

L.

Bhutan2014 45
Bhutan Trashigang 1200m, May
Bhutan2014 46
Bhutan Trashigang 1200m, May
Nepal 1994 170 ergebnis
Ost-Nepal Mewa-Khola
1850m April

Description

Bauhinia variegata, the orchid tree or kachnar, is a deciduous tree native to tropical and subtropical Asia and now pantropically naturalised, reflected in GBIF's nearly 5000 occurrences spanning India, Nepal, China, Myanmar, Thailand and Pakistan as well as introduced ranges in Brazil, the United States, Mexico, South Africa, Australia and Spain. In the Himalayan foothills it occupies warm, seasonally dry broadleaf forest, riverine slopes and disturbed ground from the plains to about 1900 m. The photographed trees from Trashigang in eastern Bhutan at 1200 m in May and from the Mewa-Khola in eastern Nepal at 1850 m in April illustrate its lower-montane habitat, where it flushes conspicuous blossoms in the dry pre-monsoon months on largely leafless branches.

It is a small to medium tree with grey-brown bark and a spreading crown. The alternate leaves are broadly ovate-cordate, bilobed for up to one-third their length into two rounded lobes giving the characteristic camel-footprint outline, with palmate venation. The showy, fragrant flowers are borne in short axillary or terminal racemes; each has five obovate, clawed petals ranging from white through pink to mauve-purple, the uppermost broader and streaked with deeper veining, and typically three to five fertile stamens. The fruit is a flat, dehiscent, woody legume up to 30 cm long containing several compressed seeds.

A member of Fabaceae (Caesalpinioideae), Bauhinia is the type genus of the diagnostically bilobed-leaved tribe Cercideae. The species is extensively cultivated as an ornamental and avenue tree, while its flower buds, bark and young pods are used as vegetables and in traditional medicine. Widespread, weedy and able to fix little nitrogen yet tolerant of poor soils, it is of Least Concern and locally invasive beyond its native range.

Author: L. · Sources: POWO (Kew), GBIF, Flora of Bhutan, Flora of China, Annotated Checklist of the Flowering Plants of Nepal, Larsen & Larsen revision of Bauhinia

Apocynaceae

Beaumontia grandiflora

by GP Jürgens

Wall.

Bhutan2014 270
Bhutan Trithangebe near a farmhouse 700m, May
Bhutan2014 271
Bhutan Trithangebe near a farmhouse 700m, May

Description

Beaumontia grandiflora is a large woody climber native to the eastern Himalaya and Indo-Chinese region, with native occurrences in India, China, Nepal, Bhutan, Thailand and Vietnam; the long list of additional countries among its roughly 602 records, spanning the Americas, Africa, the Caribbean and Oceania, reflects its extensive use as an ornamental in tropical and subtropical gardens worldwide. In the wild it is a plant of warm, humid lowland to lower-montane forest, scrambling over trees at forest margins and along streams. The photographed plant near a farmhouse at Trithangebe in Bhutan, at about 700 m and flowering in May, is consistent with its subtropical foothill habitat and its spring flowering, and hints at its frequent cultivation around dwellings.

It is a vigorous, large liana with stout woody stems exuding milky latex when cut. The leaves are opposite, simple, large, obovate to elliptic, leathery and glossy above with prominent venation and often rusty-pubescent beneath. The flowers, among the showiest in the family, are large, fragrant and trumpet-shaped, borne in terminal cymes; the corolla is broadly funnelform to campanulate, white, with five spreading lobes and a conspicuously expanded green-veined throat, giving rise to its garden name of Herald's-trumpet or Easter-lily vine. The five stamens have arrow-shaped anthers connivent around the stigma, and the fruit is a pair of large, woody, divergent follicles releasing numerous flat seeds, each with a tuft of silky hairs for wind dispersal.

Beaumontia belongs to the subfamily Apocynoideae of Apocynaceae, a family characterised by latex, contorted corolla aestivation and a specialised gynostegial pollination apparatus; the genus is allied to other tropical Asian lianas of the tribe Apocyneae. The plumed seeds and large insect-pollinated flowers fit a strategy of conspicuous floral display and wind-borne dispersal. Though valued and widely planted as a spectacular flowering vine, in its native Himalayan and Indo-Chinese range it is a natural component of subtropical forest and is not regarded as threatened.

Author: Wall. · Sources: POWO (Kew), GBIF, Flora of Bhutan, Flora of China, Flora of British India, Middleton's revisionary studies of Asian Apocynaceae

Begoniaceae

Begonia annulata

by GP Jürgens

K.Koch

Bhutan2015 146
Bhutan Galephug 700m, October

Description

Begonia annulata is a Himalayan and Indo-Burmese begonia ranging through India, Bhutan, Bangladesh, Nepal and Myanmar; GBIF lists about 109 occurrences, the lower figure reflecting its restriction to humid lowland and submontane forest. It grows in warm, shaded, perpetually moist habitats, on damp rocks, mossy banks, ravines and forest-floor seepages in evergreen broadleaved forest of the foothills and outer ranges. The photograph from Galephug in southern Bhutan at about 700 m in October shows it in the low, humid subtropical belt along the Himalayan front, fruiting late in the year where high rainfall and dense canopy sustain its succulent growth.

It is a fleshy perennial herb with an erect to ascending, jointed, translucent stem arising from a creeping rhizome or tuberous base. The leaves are alternate, conspicuously asymmetric (oblique) at the base as is typical of the genus, ovate to broadly ovate with an acuminate apex and toothed margin, palmately veined and often bearing scattered hairs, the petioles and nodes sometimes ringed (annulate, the source of the epithet). Plants are monoecious, the flowers white to pale pink and unisexual, borne in axillary cymes; staminate flowers with several stamens and pistillate flowers with a conspicuously winged inferior ovary. The fruit is a three-winged, unequally winged capsule containing very numerous minute seeds.

Begonia is one of the largest angiosperm genera, strongly radiated in the wet forests of tropical Asia, and B. annulata represents the shade- and moisture-demanding rhizomatous group of the eastern Himalaya. Its asymmetric leaves, winged capsules and dust-fine seeds are hallmarks of the family. While not formally assessed as threatened, such narrowly humid-forest specialists are sensitive to lowland deforestation and habitat drying along the Himalayan foothills.

Author: K.Koch · Sources: POWO (Kew), GBIF, Flora of Bhutan, Flora of British India (Hooker), Tebbitt Begonias: Cultivation, Identification and Natural History