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.

Orchideaceae

Dendrobium porphyrochilum

by G & P Jürgens

Lindl.

BhutanPG2011 422011 Bhutan Dendrobium porphyrochilum
Bhutan Wangdi, 2500m June
BhutanPG2011 41
Bhutan Wangdi, 2500m June

Description

Dendrobium porphyrochilum is a small epiphytic orchid of the Eastern Himalaya and adjacent Southeast Asia, recorded from India, Nepal, Thailand, China, Myanmar, Vietnam and Bhutan, with a modest set of georeferenced occurrences in GBIF. It grows as an epiphyte on the mossy trunks and branches of trees in cool, humid evergreen and mixed montane forest, where steady atmospheric moisture and a seasonal cool rest govern its growth. The species occurs at middle elevations of the temperate forest belt; the photographed plant from Wangdue in western Bhutan at about 2500 m, flowering in June, is typical of its altitudinal preference and its early-summer anthesis with the onset of the monsoon.

The plant forms small, tufted, slender, somewhat fusiform or cane-like stems clustered together, each bearing a few narrow, grass-like leaves toward the apex. The inflorescence is a short, arching to pendent raceme bearing several relatively small, nodding flowers that open more or less together. The sepals and petals are yellowish-green to olive or pale greenish, narrow and spreading. The labellum, from which the epithet derives, contrasts sharply, being deep purple to maroon-brown, recurved and obscurely lobed, sometimes bearing low keels along the disc. The short column has a foot forming a small mentum with the lateral sepals. The fruit is a small capsule.

The species belongs to Dendrobium section Oxyglossum (in the broad sense applied to small-flowered Himalayan dendrobiums of this alliance) and is distinguished among its temperate relatives by the dark, contrastingly coloured lip set against pale tepals. As a forest epiphyte of restricted abundance, it is dependent on intact, humid mid-elevation woodland and is therefore susceptible to deforestation and to over-collection, although it has not been formally assessed for conservation status.

Author: Lindl. · Sources: POWO (Kew), GBIF, Flora of China, The Orchids of Bhutan (Pearce & Cribb), Dendrobium and its Allies (Lavarack et al.)

Orchideaceae

Dendrobium rotundatum

by GP Jürgens

Hook.f.

Nepal 97 424 P815
Nepal Tashigaon 3100m May

Description

Dendrobium rotundatum Hook.f. is an epiphytic orchid of the eastern Himalaya and adjacent ranges, distributed through Nepal, northern India, Bhutan and into south-western China and Myanmar, with a GBIF record of about 122 occurrences (including a cultivated citation from Belgium) that reflects its relatively narrow distribution and inconspicuous habit. It grows perched on the trunks and branches of trees in cool, humid temperate broadleaf and mixed forest, where mossy bark and high atmospheric moisture sustain its epiphytic roots. The illustrated plant was recorded at Tashigaon in eastern Nepal at 3100 m in May, an elevation at the cool, montane end of the genus's range and a season corresponding to flowering as spring conditions return to the forest.

It is a small epiphyte with slender, often pendent to ascending stems (pseudobulbs) that are somewhat swollen and jointed, bearing distichous, thin-textured, oblong to lanceolate leaves along their length, these often deciduous in the dormant season. The flowers are produced from the nodes, solitary or few together, and are relatively small; the sepals and petals are subequal, with the lateral sepals united at the base to the column foot to form a short, rounded mentum or chin, an attribute echoed in the epithet rotundatum. The labellum is entire to obscurely three-lobed, the disc often bearing low ridges or a callus, and the column is short and footed in the typical Dendrobium pattern. The fruit is a ribbed, dehiscent capsule releasing dust-like seeds.

Dendrobium, with its centre of diversity in tropical and subtropical Asia, is one of the largest orchid genera, and the cool-growing, small-flowered Himalayan species such as D. rotundatum represent its montane, temperate fringe. As an epiphyte it depends on intact, humid old-growth forest and on mycorrhizal fungi for seed germination, making it sensitive to logging and habitat degradation. Like most orchids it is listed under CITES Appendix II to regulate international trade, and although not separately assessed as threatened, its restricted range and habitat specificity warrant ongoing monitoring of wild populations.

Author: Hook.f. · Sources: POWO (Kew), GBIF, Flora of China, Orchids of Nepal (Raskoti), The Genus Dendrobium (Wood)

Orchideaceae

Dendrobium transparens 

by GP Jürgens

Wall. ex Lindl.

Nepal 2001 474 ergebnis ergebnis scaled
Nepal 2001 475 ergebnis ergebnis scaled
Nepal (Gorkha) Labubhesi 1200m, May

Description

Dendrobium transparens is an epiphytic orchid distributed across the eastern and central Himalaya and into the Indo-Burmese region, recorded from India, Nepal, Bhutan, China, Myanmar and Thailand, with introduced or cultivated occurrences in western Europe. The species favours warm-temperate to subtropical broad-leaved forest, growing on tree trunks and mossy branches between roughly 800 and 1800 m. The photographed plant from Gorkha at Labubhesi, central Nepal, around 1200 m and flowering in May, is typical of its preferred mid-elevation, humid forested ravines where seasonal monsoon moisture and bright filtered light coincide.

The plant forms slender, pendent or sub-erect, cane-like stems that are somewhat flattened and longitudinally grooved, sheathed by membranous leaf-bases. The leaves are distichous, narrowly lanceolate, thin-textured and deciduous, leaving the leafless canes to bear flowers. Inflorescences are short, lateral, two- to three-flowered fascicles from the nodes of older stems. The flowers are translucent white to pale rose, the sepals and petals delicate and spreading; the labellum is broadly obovate to sub-orbicular, often marked with two deep magenta to purple blotches at the throat, and the short mentum gives the bloom its semi-pendent posture.

The specific epithet transparens alludes to the thin, almost translucent perianth segments. Within Dendrobium it belongs among the deciduous-leaved, soft-caned sections allied to D. nobile, a complex of considerable horticultural interest. As with most Himalayan epiphytic orchids, it is dependent on intact forest cover and mycorrhizal associations, and is vulnerable to habitat clearance and collection pressure, though it remains locally frequent across its broad range.

Author: Wall. ex Lindl. · Sources: POWO (Kew), GBIF, Flora of China Vol. 25, Flora of Bhutan Vol. 3, Flora of Nepal, The Genus Dendrobium (Wood)

Hydrangeaceae

Deutzia corymbosa

by GP Jürgens

R.Br. ex G.Don

BhutanPG2011 820 01 01
Bhutan Chele-La, 3400m July

Description

Deutzia corymbosa is a flowering shrub of Himalayan temperate forests, with GBIF documenting 99 occurrences from India, China, Nepal and Bhutan, plus a few cultivated or vouchered records from Europe and North America. It grows on forest margins, shrubby slopes, rocky banks and clearings in the temperate to lower subalpine zone, often in mixed broadleaved and conifer forest. It was recorded on the Chele-La in Bhutan at about 3400 m in July, a high-summer flowering at the upper part of its range where the white corymbs are conspicuous against the montane scrub.

It is a deciduous shrub with erect to arching branches and exfoliating bark on the older stems. The leaves are opposite, ovate to ovate-lanceolate, acuminate, finely serrate, and clothed in stellate hairs that give the foliage a slightly rough texture characteristic of the genus. The inflorescence is a flattened, many-flowered corymb, as the epithet corymbosa indicates; each flower has five white, spreading petals, five sepals, ten stamens with the toothed or winged filaments typical of Deutzia, and three to four styles. The fruit is a small, hemispherical to top-shaped, several-valved capsule.

Deutzia (Hydrangeaceae) comprises shrubs of east Asia, Central America and the Himalaya, with a rich Sino-Himalayan representation and many ornamental species; the corymbose-inflorescenced group to which D. corymbosa belongs is distinctive within the genus. Widely grown and hybridised in horticulture, it is common across its broad native range and not of conservation concern. As an element of the temperate Himalayan shrub layer, it is of biogeographic interest within the disjunct east-Asian to Himalayan distribution pattern shown by many Hydrangeaceae.

Sources: POWO (Kew), GBIF, Flora of China, Flora of Bhutan, Annotated Checklist of the Flowering Plants of Nepal, Zaikonnikova's monograph of Deutzia (Hydrangeaceae)

Hydrangeaceae

Deutzia staminea

by GP Jürgens

R.Br. ex Wall.

Nepal 97 304 P605
Nepal Honggaon 2360m, May

Description

Deutzia staminea is a deciduous shrub distributed across the western and central Himalayas, from Pakistan through northern India and Nepal to Bhutan, with populations extending into southwest China and northern Myanmar. GBIF records approximately 390 occurrences, with the majority from India and Nepal. The species occupies dry to mesic slopes, open forests, scrublands, and rocky hillsides at elevations of 1,500–3,200 m. At Honggaon in central Nepal at 2,360 m, it inhabits open Pinus–Quercus forests and rocky banks, where it flowers prolifically in May during the pre-monsoon season.
Deutzia staminea is a deciduous shrub reaching 1.5–4 m in height, with greyish-brown bark that exfoliates in thin flakes on older stems. Leaves are opposite, ovate to lanceolate, 3–8 cm long, with serrate margins and a rough texture from stellate trichomes on both surfaces. The inflorescence is a terminal corymb or panicle of 5–20 flowers. Flowers are pentamerous, 12–18 mm in diameter, with white petals that are oblong-elliptic and spreading. The stamens, 10 in number, are distinctive: the filaments are broadly winged and toothed at the apex, exceeding the petals — a character reflected in the specific epithet 'staminea.' The fruit is a hemispheric capsule, 4–6 mm across, dehiscing by 3–4 valves and releasing numerous small seeds.
Deutzia staminea is the most widespread Himalayan representative of the genus and is distinguished from the closely related D. compacta by its prominently toothed stamen filaments and generally laxer inflorescences. The species serves as an important early-season nectar resource for pollinators in mid-elevation Himalayan landscapes, where relatively few shrubs are in flower during the pre-monsoon period. It is occasionally cultivated in European gardens and has been in cultivation since its introduction by Wallich in the early nineteenth century.

Author: R.Br. ex Wall. · Sources: POWO (Kew), GBIF, Flora of China Vol. 8, Flora of Pakistan Vol. 192, Polunin & Stainton: Flowers of the Himalaya (1984)

Diapensiaceae

Diapensia himalaica

by GP Jürgens

Hook.f. & Thomson

BhutanPG2011 447
Bhutan Jule-Tso, 4100m June

Description

Diapensia himalaica Hook.f. & Thomson is a high-alpine cushion plant of the Sino-Himalayan mountains, recorded from China, India, Nepal, Bhutan and Myanmar (CN, IN, NP, BT, MM), with GBIF documenting some 304 occurrences. It is a plant of the upper alpine and subnival belt, on exposed rocky ridges, gravelly slopes, moraines and turf margins, generally above 4000 m where wind exposure and a short growing season prevail. The Bhutanese material from Jule-Tso at 4100 m in June illustrates its early-summer flowering after snow-melt, when the cushions are studded with relatively large solitary flowers.

It forms a compact, evergreen, woody cushion of densely crowded shoots clothed in small, leathery, imbricate leaves. These are narrowly spathulate to oblong, sessile, with a thickened entire margin and a coriaceous texture resisting desiccation. The flowers are solitary and terminal on short stalks scarcely exceeding the cushion, actinomorphic and five-merous, with a persistent calyx and a campanulate to rotate corolla of fused white to pale pink petals; the five stamens are adnate to the corolla tube. The fruit is a small loculicidal capsule with numerous minute wind-dispersed seeds.

Diapensia is the type genus of the small, isolated family Diapensiaceae, an arctic-alpine lineage of ericalean affinity, and D. himalaica is the Himalayan vicariant of the circumboreal D. lapponica complex. The compact cushion habit is a classic adaptation to cold, wind-swept, nutrient-poor high mountains. Its biogeographic importance lies in linking the Himalayan high-alpine flora to arctic and boreal cushion-plant communities, and as a slow-growing specialist it is sensitive to climate change.

Author: Hook.f. & Thomson · Sources: POWO (Kew), GBIF, Flora of Bhutan Vol. 2, Flora of China Vol. 14, Flora of Nepal, Scott & Day monograph of the Diapensiaceae

Ranunculaceae

Dichocarpum adiantifolium

by GP Jürgens

(Hook.f. & Thomson) W.T.Wang & P.K.Hsiao

Nepal 97 310 G614
Nepal Honggaon 2300m May
Sikkim 2006 33 2 ergebnis
India West-Bengal Tonglu 3200m, May

Description

Dichocarpum adiantifolium is a slender woodland buttercup relative of the Sino-Himalayan region, distributed through Taiwan, China, India, Nepal, Bhutan and Myanmar, with the comparatively rich total of about 286 GBIF records. It grows in cool, shaded, humus-rich situations: moist temperate forest floors, mossy rocks, ravine banks and streamsides, generally between about 2000 and 3500 m. The collections illustrated, from Honggaon in Nepal at around 2300 m and Tonglu in West Bengal at about 3200 m, both in May, represent its typical spring-flowering forest habitat.

It is a delicate, glabrous perennial herb arising from a short rhizome. The leaves are mostly basal, long-petiolate and compound, divided into numerous small, thin, fan-shaped to obovate leaflets that recall the fronds of a maidenhair fern (Adiantum), hence the epithet. Slender scapes bear loose, few-flowered cymes of small flowers, each with five white, petaloid sepals and small tubular or two-lipped nectary petals, numerous stamens and usually two carpels. The diagnostic fruit is a pair of divergent, flattened follicles spreading widely at maturity, a feature reflected in the generic name (from the Greek for divided fruit).

Dichocarpum is a small east Asian and Himalayan genus segregated from Isopyrum and allied to Thalictrum and Aquilegia within the Ranunculaceae; D. adiantifolium was originally described under Isopyrum and later transferred by Wang and Hsiao. The paired spreading follicles and ferny foliage make it readily recognisable. It is a fairly widespread forest-understorey species and is not regarded as threatened, though as a shade-demanding mesophyte it depends on intact, humid temperate forest and would be sensitive to logging and forest fragmentation.

Author: (Hook.f. & Thomson) W.T.Wang & P.K.Hsiao · Sources: POWO (Kew), GBIF, Flora of China, Flora of Bhutan, Annotated Checklist of the Flowering Plants of Nepal, Wang & Hsiao Revision of the Genus Dichocarpum

Papaveraceae

Dicranostigma lactucoides

by G & P Jürgens

Hook.f. & Thomson

Nepal 99 399 ergebnis
West-Nepal Talphi 2830m, June
Nepal 99 551 ergebnis
West-Nepal Talphi 2830m, June
Nepal 99 552 ergebnis
West-Nepal Talphi 2830m, June

Description

Dicranostigma lactucoides Hook.f. & Thomson is a yellow-flowered Himalayan poppy relative known from about 145 records in Nepal, China, India and Bhutan. It is a plant of dry, open, often disturbed ground: stony slopes, rock crevices, river terraces, field margins and roadside banks in the inner valleys, generally in the warm-temperate to subalpine belt between roughly 2500 and 4000 m. The individual photographed at Talphi in West Nepal at 2830 m in June reflects its preference for sunny, well-drained, somewhat ruderal sites in the comparatively arid trans-Himalayan rain-shadow.

The species is an erect annual to short-lived perennial herb containing yellow to orange latex. The basal leaves form a rosette and are oblanceolate in outline, pinnately lobed to lyrate-pinnatifid with a large terminal lobe, glaucous and somewhat lettuce-like, whence the epithet "lactucoides." Cauline leaves are smaller and clasping. The flowers are borne on slender pedicels; two caducous sepals enclose four broad, crinkled, bright yellow petals surrounding numerous stamens. The fruit is the diagnostic feature of the genus: a slender, elongate, more or less cylindrical siliqua-like capsule dehiscing from the apex, crowned by a short style with a forked (bifid) stigma, and releasing many small seeds.

Dicranostigma is a small Asian genus close to Glaucium and Chelidonium in tribe Chelidonieae, distinguished by its elongate capsule and divided stigma; D. lactucoides is its principal Himalayan representative. Like its allies it contains benzylisoquinoline alkaloids and has been used locally in folk medicine. As a ruderal, weedy colonist of open ground it is resilient to moderate disturbance and is not regarded as threatened across its Sino-Himalayan range.

Author: Hook.f. & Thomson · Sources: POWO (Kew), GBIF, Flora of China, Flora of Nepal, Hooker's Flora of British India, monograph of Papaveraceae tribe Chelidonieae

Didymocarpinae

Didymocarpus aurantiacus

by GP Jürgens

C.B.Clarke

Sikkim2003 22 G26
Sikkim Rathong-Chu 1200 m, August

Description

Didymocarpus aurantiacus is an eastern Himalayan gesneriad recorded from India, Nepal and Bhutan, with around 33 occurrences concentrated in the wet, monsoon-drenched subtropical to lower temperate belt of Sikkim, Darjeeling and adjacent regions. It is a lithophyte and epipetric herb growing on shaded, moss-covered rocks, cliff faces and damp ravine walls within evergreen broad-leaved forest, typically between roughly 1000 and 2000 m. The illustrated material from the Rathong-Chu valley in Sikkim at 1200 m, flowering in August, reflects its main flowering during the rainy season, when the humid rock habitats it favours are kept constantly moist by mist and seepage.

It is a small perennial herb with a short rhizomatous base and crowded, opposite or subrosulate leaves. The lamina is ovate to elliptic, with a crenate-serrate margin, an acute to acuminate apex and a thinly hairy surface, the venation impressed above and prominent beneath. The inflorescence is an axillary cyme borne on a slender peduncle. The flowers have a tubular, lobed calyx and a tubular, somewhat ventricose corolla that is orange to orange-yellow (as the epithet aurantiacus indicates), two-lipped with a shorter upper and spreading lower lip. There are two fertile stamens with cohering anthers and staminodes; the gynoecium develops into the elongate, septicidal, two-valved capsule characteristic of the genus.

The input places this taxon under "Didymocarpinae", which is the subtribe within tribe Trichosporeae of the Gesneriaceae rather than a family; the species is correctly accommodated in the genus Didymocarpus. The name D. aurantiacus C.B.Clarke is accepted. As a narrow-ranged rock specialist tied to perhumid forest, it is dependent on intact, shaded microhabitats and is therefore potentially sensitive to deforestation and habitat drying, though it has not been formally assessed.

Author: C.B.Clarke · Sources: POWO (Kew), GBIF, Flora of Bhutan Vol. 2, Flora of Nepal, Weber Gesneriaceae of the World (monograph), Clarke Commelynaceae et Cyrtandreae Bengalenses

Didymocarpinae

Didymocarpus oblongus

by G & P Jürgens

Wall.

Sikkim 2006 449 ergebnis
India West-Bengal, Tolung 2450m, May

Description

Didymocarpus oblongus is a relatively uncommon gesneriad endemic to the eastern Himalaya, recorded from Nepal, northeast India (Sikkim, Darjeeling, Assam), Bhutan, and adjacent parts of southern China (Xizang, Yunnan). It inhabits shaded, damp rock faces, mossy cliff ledges, and steep earth banks in montane broadleaved and mixed forests, typically at elevations between 1,800 and 3,000 m. The species has been documented from the Tolung area of West Bengal at approximately 2,450 m, where it grows in the moist understorey of temperate forests during the spring season.
The plant is a perennial herb with a short, erect stem 5–15 cm tall, arising from a fleshy rootstock. Leaves are arranged in an opposite, often crowded rosette-like cluster near the stem apex; they are oblanceolate to oblong, 5–15 cm long and 2–5 cm wide, with a crenate to serrate margin, the upper surface dark green and sparsely pilose, the lower surface paler and more densely pubescent. The inflorescence is a lax cyme of 2–6 flowers borne on a slender peduncle 5–10 cm long. The calyx is tubular, five-lobed. The corolla is tubular-funnelform, 2–3 cm long, typically pale purple to lavender with darker markings in the throat. Stamens are two, with the filaments inserted at mid-tube; the anthers are coherent face to face. The fruit is a slender, elongate capsule 2–4 cm long, dehiscing loculicidally.
Didymocarpus is a genus of approximately 100 species centred in mainland Asia, with the Himalayan region representing a significant centre of diversity. D. oblongus is distinguished from allied species by its oblong leaf shape, relatively long peduncles, and high-elevation habitat preference. With only 88 occurrence records in GBIF and a restricted distribution along the eastern Himalayan arc, the species warrants conservation attention, particularly as its cliff-face and forest-understorey habitats are sensitive to deforestation and landslide disturbance.

Author: Wall. · Sources: POWO (Kew), GBIF, Flora of Bhutan Vol. 2, Flora of China Vol. 18, Möller & Clark: Gesneriaceae classification (2013)