Tag:

Subalpine (2500-3500 m)

Ericaceae

Rhododendron cinnabarinum

by GP Jürgens

Hook. f.

Bhutan2014 877
Bhutan Chele-La 2850m, May
Bhutan2014 882
Bhutan Chele-La 2850m, May
Bh2008 221 P349
Bhutan Tumching-La, 3400m April
Bh2008 222 G350
Bhutan Tumching-La, 3400m April
Sikkim2003 191 G262
Sikkim Dzongri 3900m 08.2003

Description

Rhododendron cinnabarinum is an Eastern Himalayan species native to Bhutan, Sikkim and adjacent northeastern India, Nepal and southern Tibet (China), the nearly 768 records also reflecting its popularity in cultivation in Britain, North America and elsewhere. It is a shrub of the cool temperate to subalpine zone, the images documenting plants on the Chele-La in Bhutan at about 2850 m in May, the Tumching-La at about 3400 m in April, and Dzongri in Sikkim near 3900 m. It grows in fir and mixed forest, rhododendron thickets, forest margins and open subalpine scrub on moist, acidic, humus-rich slopes within the monsoon-influenced humid belt of the range.

It is an evergreen shrub reaching one to several metres, with smooth bark and aromatic foliage. The leaves are elliptic to obovate, conspicuously glaucous-blue when young and densely scaly (lepidote) beneath, the scales being diagnostic of the lepidote rhododendrons. The pendulous, tubular-campanulate to narrowly funnel-shaped flowers are borne in small terminal trusses and are noted for their waxy texture and remarkable colour range, from cinnabar-red and orange to plum and yellow; the ten stamens and the style are enclosed within the elongate corolla tube, which matures into a scaly capsule.

Described by J.D. Hooker, the species is placed in subgenus Rhododendron, subsection Cinnabarina, the only members of the lepidote group with markedly tubular, drooping corollas suited to pollination by birds and long-tongued insects. It is variable across its range, with several recognised subspecies and varieties differing in flower colour and foliage, and is an important parent in horticulture. Locally common in suitable habitat and widely cultivated, it is not regarded as globally threatened, though parts of its native forest are under pressure.

Author: Hook. f. · Sources: POWO (Kew), GBIF, Flora of Bhutan, Flora of China, The Genus Rhododendron (Royal Botanic Garden Edinburgh)

Ericaceae

Rhododendron dalhousieae

by GP Jürgens

Hook. f.

Bh09 237 P397
Bhutan Wangdi 1950m, June
Bh09 238 G399
Bhutan Wangdi 1950m, June
Nepal 97 314 P620
Nepal Honggaon 2360m May
Nepal 97 418 P807
Nepal Taskigaon 3000m May
Sikkim 2006 172 ergebnis
Sikkim 2006 175 ergebnis
India West-Bengal, Samadan 2400m, May

Description

Rhododendron dalhousieae is an epiphytic or terrestrial shrub of the eastern Himalaya, distributed across India, Nepal, Bhutan and adjacent China; its c. 149 georeferenced records track the wet temperate forest belt (records from Britain and New Zealand reflect its long history in cultivation). It grows in humid broadleaf and Rhododendron-rich forest, often perched on mossy trunks and rocks or on steep banks, chiefly between 1800 and 3000 m. The image documents populations across its range, from Wangdi in Bhutan at 1950 m to Nepal's Honggaon and Taskigaon (2360-3000 m) and Samadan in West Bengal at 2400 m, flowering from May into June in the cloud-forest zone.

It is a straggling, sparsely branched shrub 1-3 m tall, frequently epiphytic, with peeling bark and large, obovate to elliptic leaves clustered toward the branch tips, glaucous beneath and bearing scattered scales. The flowers are among the most spectacular of Himalayan rhododendrons: borne in lax trusses of two to six, each broadly funnel-campanulate, 7-12 cm long, fragrant, white often flushed with pale yellow or pink, with a long tube. The ten stamens and slender style are enclosed within the corolla, and the scaly ovary matures into an elongate capsule splitting to release numerous minute winged seeds.

Described by Hooker f. (Hook. f.) from his Sikkim explorations, R. dalhousieae belongs to Rhododendron subgenus Rhododendron, section Rhododendron (the lepidote or scaly-leaved rhododendrons), and is named for Lady Dalhousie. Its large, fragrant, pale flowers suggest pollination by moths and large bees. Long prized in horticulture, it is widespread but locally uncommon and dependent on intact humid forest; habitat loss makes some populations vulnerable, though it is not formally threatened.

Author: Hook. f. · Sources: POWO (Kew), GBIF, Flora of Bhutan, Flora of China, Flora of Bhutan and Sikkim, The Genus Rhododendron monograph (Edinburgh, Ericaceae)

Ericaceae

Rhododendron delavayi

by GP Jürgens

Franch.

Bh2008 21 P38
Bhutan Thimphu-Chu, 2800m
Bh2008 23 P40
Bhutan Thimphu-Chu, 2800m

Description

Rhododendron delavayi Franch. is a shrub or small tree of the Sino-Himalayan region, distributed through south-western China (Yunnan, Guizhou, Sichuan, Xizang), Myanmar, Thailand, Vietnam, north-eastern India, Bhutan and Nepal, with horticultural records from the United Kingdom, United States, Canada and Belgium contributing to a GBIF total of around 1,290 occurrences. It grows in evergreen broadleaf forest, pine forest, open thickets and on rocky montane slopes, typically on acidic soils in the warm-temperate to lower montane belt. The illustrated plant comes from the Thimphu-Chu valley in Bhutan at about 2800 m, an elevation characteristic of the species where it forms a conspicuous element of the forest canopy and understorey and flowers in spring.

It is an evergreen shrub to small tree with stout branches and a thick, often flaking bark. The leaves are leathery, oblong-lanceolate to oblanceolate, dark green and glabrous above, the lower surface densely covered with a felted, persistent, fawn to greyish or whitish tomentum (indumentum) that is diagnostic of the species. The flowers are borne in dense, rounded, terminal trusses; each is broadly campanulate with a deep crimson to scarlet corolla of about five lobes, marked at the base with darker nectar pouches, and contains about ten stamens and a glabrous or hairy ovary with a long style. The fruit is a woody, cylindrical, ribbed capsule dehiscing by valves to release numerous minute seeds.

Rhododendron delavayi is the type species of subsection Arborea and is closely related to the Himalayan R. arboreum, with which it intergrades and shares the tree habit and red flowers; it is distinguished by its compact indumentum and floral details. Ecologically it is bird- and insect-pollinated and is a dominant component of warm broadleaf forest, while in cultivation it is valued as a parent of many hybrids. Although widespread, it is locally affected by deforestation and habitat conversion in parts of its range, but overall it remains common and is not regarded as globally threatened.

Author: Franch. · Sources: POWO (Kew), GBIF, Flora of China, Flora of Bhutan, The Genus Rhododendron (Edinburgh, Chamberlain et al.)

Ericaceae

Rhododendron edgeworthii

by GP Jürgens

Hook. f.

Bhutan2014 315
Bhutan Tumching-La 2600m, May
Bhutan2014 317
Bhutan Tumching-La 2600m, May
Bh2008 159 P260
Bhutan Chendebji, 2600m April
Bh2008 160 P261
Bhutan Chendebji, 2600m April

Description

Rhododendron edgeworthii is distributed through the eastern Himalaya and adjacent montane south-west China, with native records spanning Bhutan, north-east India, Myanmar and Yunnan and Xizang (China); the remaining records among 665 georeferenced occurrences (United States, Canada, New Zealand, Britain, Belgium, Korea) reflect its long cultivation as an ornamental. It is characteristically epiphytic or saxicolous, growing on mossy tree trunks, boulders and humus-rich banks in cool, humid temperate forest with oak, Tsuga and other rhododendrons. The species was collected in Bhutan at Tumching-La and Chendebji at around 2600 m, consistent with its typical altitudinal range of roughly 2000-3700 m in the upper temperate zone.

It is a straggling, often epiphytic shrub to about 2-3 m, the young shoots and undersides of the leaves densely clothed in tawny, woolly-tomentose to setose indumentum. The leaves are elliptic to ovate, leathery, bullate-rugose above and conspicuously brown-felted beneath. The flowers, borne in lax trusses of two or three, are large, broadly funnelform-campanular, white usually flushed rose, and strongly fragrant, with the outer surface scaly and the lobes spreading; stamens are typically ten and the ovary densely scaly, ripening into a scaly capsule.

Within the genus the species belongs to subgenus Rhododendron (lepidote rhododendrons), section Rhododendron, subsection Edgeworthia, distinguished by the combination of bullate foliage, dense woolly indumentum and large scented blooms. It hybridises readily in cultivation and has contributed to fragrant hybrid groups. Though locally frequent across a wide range and assessed as of Least Concern, its dependence on undisturbed humid forest makes it sensitive to deforestation and collection pressure.

Author: Hook. f. · Sources: POWO (Kew), GBIF, Flora of Bhutan, Flora of China, The Rhododendron Handbook (Royal Horticultural Society), Cox & Cox The Encyclopedia of Rhododendron Species

Ericaceae

Rhododendron falconeri

by GP Jürgens

Hook.f.

Bhutan2014 349
Bhutan Tumching-La 3000m, May
Bh2008 100 P160
Bhutan Nabding, 2600m April
Bh2008 101 P161
Bhutan Nabding, 2600m April
Sikkim2004 24 P45
Sikkim West-Bengal, Sambon 1850m April
Sikkim2004 35 G61
Sikkim West-Bengal, Sambon 1850m April
Sikkim2004 31 P53 ergebnis
Sikkim Bersay 2810m, April

Description

Rhododendron falconeri is a large-leaved arborescent rhododendron native to the eastern Himalaya, occurring in Nepal, India (Sikkim, Darjeeling), Bhutan and adjacent China; the additional countries listed in GBIF (Great Britain, Canada, Belgium, Korea and others among 316 occurrences) reflect cultivated and herbarium records from botanic gardens. It grows in cool, humid temperate forest between roughly 2400 and 3300 m, forming a conspicuous component of the upper broadleaved and rhododendron-magnolia zone. The collection localities in the image caption, spanning Tumching-La and Nabding in Bhutan and Sambon and Bersay in Sikkim and West Bengal between 1850 and 3000 m in April and May, capture its flowering on misty ridge forests during the pre-monsoon.

The species is an evergreen shrub or small tree to 12 m with rough, flaking bark and stout shoots. Its very large obovate to elliptic leaves, up to 30 cm long, are dark green and rugose above and clothed beneath with a dense rusty to fawn indumentum of branched hairs, a diagnostic feature. The flowers are borne in dense rounded trusses of fifteen to twenty-five; each corolla is fleshy, campanulate, eight- to ten-lobed, creamy white to pale yellow and marked with a deep purple basal blotch. Fruit is a stout, curved, woody dehiscent capsule releasing numerous minute winged seeds.

Placed in subgenus Hymenanthes, subsection Falconera, R. falconeri is allied to R. hodgsonii and is among the most celebrated big-leaf rhododendrons, cultivated since its introduction by Hooker. The thick leaf indumentum and large foliage are adaptations to cool, fog-laden montane conditions, and it is pollinated chiefly by birds and large insects. While locally common and not globally threatened, Himalayan populations are pressured by fuelwood cutting, forest clearance and climate-driven upslope shifts.

Author: Hook.f. · Sources: POWO (Kew), GBIF, Flora of Bhutan, The Genus Rhododendron (Royal Botanic Garden Edinburgh), Hooker Rhododendrons of Sikkim-Himalaya

Ericaceae

Rhododendron glaucophyllum

by GP Jürgens

Rehder

Sikkim2004 392 P672
Sikkim (India), Lachung 3100 m
Sikkim2004 386 P664
Sikkim (India), Lachung 3100 m, May

Description

Rhododendron glaucophyllum is an Eastern Himalayan shrub distributed across Sikkim and adjacent India, Nepal, Bhutan and parts of south-western China and Myanmar. Its 172 GBIF records concentrate in this native range, the British, Canadian, New Zealand and United States points reflecting its long cultivation as an ornamental rhododendron. It grows in subalpine and alpine shrubberies, on open rocky slopes, cliffs, forest margins and moist banks, typically between about 2700 and 3700 m. The plant photographed at Lachung in Sikkim at 3100 m in May illustrates the species flowering in late spring within the cool, humid montane belt of the Eastern Himalaya.

It is a small, aromatic, evergreen shrub with peeling, papery bark and elliptic to oblong leaves that are dark green above and conspicuously glaucous and densely scaly (lepidote) beneath, the source of the epithet glaucophyllum. The flowers are borne in small terminal trusses; the campanulate corolla is pink to rose, sometimes paler or white, with the calyx well-developed and lobed, a distinctive feature of the species. Ten stamens and a lepidote ovary are typical of its subgenus. The fruit is a small, scaly, dehiscent capsule releasing numerous tiny seeds.

The species belongs to Rhododendron subgenus Rhododendron, section Rhododendron (the lepidote, scaly-leaved rhododendrons), and within it to the glaucophyllum group, characterised by aromatic foliage and a prominent calyx. Several varieties have been recognised across its range. Widely distributed and locally common, and well established in cultivation, R. glaucophyllum is not considered threatened, forming an attractive element of Eastern Himalayan subalpine scrub.

Author: Rehder · Sources: POWO (Kew), GBIF, Flora of Bhutan, Flora of China, The Rhododendron Handbook (RHS)

Ericaceae

Rhododendron griffithianum

by GP Jürgens

Wight

Bhutan2014 458
Yatong-La 3200m, May
Bh2008 150 P248
Yatong-La 3200m, May
Bh2008 151 P249
Yatong-La 3200m, May
Nepal 1994 254 ergebnis
Ost-Nepal Milka-Danda 2800m May 

Description

Rhododendron griffithianum is an eastern Himalayan species centred on India (Sikkim, Arunachal), Bhutan, Nepal and adjacent China, with about 219 georeferenced records; further occurrences in Britain, the Netherlands, Canada, the United States and New Zealand reflect its long cultivation as a horticultural ornamental and parent of hybrids. It grows in cool, humid temperate forest, on shaded ridges and ravine sides, often as an understorey or forest-margin shrub between roughly 2500 and 3300 m. The photographed plants from Yatong-La at 3200 m and the East Nepal Milke Danda at 2800 m, flowering in May, typify this moist mid-montane belt.

It is a large evergreen shrub to small tree with smooth, peeling, reddish-brown bark. The leaves are elliptic-oblong, leathery, glabrous and somewhat glaucous beneath, with a rounded base and prominent midrib. The inflorescence is a lax truss of few large flowers; the corolla is broadly campanulate, white sometimes flushed pink, faintly fragrant, and among the largest of any Himalayan rhododendron, with a calyx that is unusually well developed and lobed. The fruit is an elongate, ribbed, dehiscent capsule releasing numerous minute winged seeds.

Classified in subgenus Hymenanthes, R. griffithianum has been horticulturally pivotal, contributing its size and corolla form to many hardy garden hybrids. In the wild it occupies a narrow, oceanic-monsoon climatic band, and its dependence on undisturbed humid forest renders it sensitive to logging, grazing and warming, of biogeographic interest as an indicator of the wet eastern Himalayan forest flora.

Author: Wight · Sources: POWO (Kew), GBIF, Flora of Bhutan, Flora of China, The Genus Rhododendron (Royal Botanic Garden Edinburgh)

Ericaceae

Rhododendron hodgsonii

by GP Jürgens

Hook. f.

Bhutan2014 502
Bhutan Yatong-La 3250m, May
Bhutan2014 508
Bhutan Yatong-La 3250m, May
Bh2008 129 G216
Bhutan Pele-La, 3000m April
Bh2008 594 G889
Bhutan Chele-La 3900m April
Nepal 1994 209 ergebnis
Ost-Nepal Mewa-Khola 2500m April 

Description

Rhododendron hodgsonii is a large evergreen shrub or small tree of the temperate and subalpine zones of the eastern Himalaya, native to India (Sikkim, Arunachal), Nepal, Bhutan and adjacent China, with over 440 georeferenced records (many of the further-flung being cultivated specimens in botanic gardens). It forms a conspicuous component of the upper broad-leaved and conifer-Rhododendron forests, typically between about 2500 and 3700 m. The photographed plants span this range in Bhutan, from Pele-La and Chele-La to Yatong-La at 3000-3900 m, and in eastern Nepal at Mewa-Khola at 2500 m, flowering from April into May as the snow recedes from the high passes.

The species is distinguished by its smooth, fawn to plum-coloured peeling bark and very large, leathery, obovate-elliptic leaves up to 30 cm long, dark glossy green above and clothed beneath with a thin, silvery to fawn, plastered indumentum. The flowers are borne in dense, rounded terminal trusses of fifteen to twenty-five blooms; the corolla is fleshy, campanulate and eight- to ten-lobed, ranging from magenta-rose to pale pink with darker nectar pouches at the base. The stamens are numerous and the stout style ends in a broad capitate stigma. The fruit is a stout, curved, woody capsule.

Rhododendron hodgsonii belongs to subgenus Hymenanthes, subsection Falconera, allied to R. falconeri but separable by its thinner leaf indumentum and rich magenta corolla. Named for Brian Houghton Hodgson, it is a keystone of the Himalayan Rhododendron forests, its leaves traditionally used for wrapping and its thickets providing shelter for montane wildlife. Locally abundant and not threatened, it is widely grown in temperate gardens.

Author: Hook. f. · Sources: POWO (Kew), GBIF, Flora of Bhutan, The Genus Rhododendron (Royal Botanic Garden Edinburgh), Rhododendrons of Sikkim-Himalaya (Hooker)

Ericaceae

Rhododendron kendrickii

by GP Jürgens

Nutt.

Bhutan2014 334
Bhutan Tumching-La 2900m, May
Bhutan2014 359
Bhutan Tumching-La 2900m, May

Description

Rhododendron kendrickii is an eastern Himalayan species centred on Bhutan, north-east India (Arunachal Pradesh) and adjacent south-west China and northern Myanmar, with Nepal at the western limit; the 71 georeferenced records also include cultivated material in New Zealand. It is a component of cool, humid temperate forest, growing in mixed evergreen woodland, on forest margins and steep mossy slopes. The Bhutan collection at Tumching-La at about 2900 m sits squarely within its typical altitudinal range of roughly 2400-3300 m in the upper temperate broadleaved zone, where it flowers in spring.

It is an evergreen shrub or small tree, often 3-6 m tall, with smooth bark and stout branchlets. The leaves are oblong-lanceolate to narrowly elliptic, leathery, acuminate, dark glossy green above and pale beneath, with a prominent midrib and narrowly recurved margins. The flowers are borne in compact, many-flowered trusses; the corolla is tubular-campanulate, fleshy, and rich crimson to scarlet with darker nectar pouches at the base. Stamens are typically ten, the style glabrous, and the ovary develops into a woody, curved capsule.

The species belongs to subgenus Hymenanthes, the elepidote (non-scaly) rhododendrons, within subsection Irrorata, characterised by tubular red corollas and glabrous ovaries. The brightly coloured, nectar-rich flowers are adapted to bird and insect pollination in the spring monsoon margin. Locally common within its range and not currently regarded as threatened, it nonetheless depends on intact temperate forest and is affected by logging, grazing and fire.

Author: Nutt. · Sources: POWO (Kew), GBIF, Flora of Bhutan, Flora of China, Cox & Cox The Encyclopedia of Rhododendron Species, The Rhododendron Handbook (Royal Horticultural Society)

Ericaceae

Rhododendron kesangiae

by GP Jürgens

D.G.Long & Rushforth

Bhutan2014 426
Bhutan Yatong-La 2900m, May
Bhutan2014 431
Bhutan Yatong-La 2900m, May
Bh2008 104 P168
Bhutan Nobding, 2700m April
Bh2008 370 P573
Bhutan Nobding, 2700m April
Bh2008 227 P359
Bhutan Nobding, 2700m April
Bh09 280 G462
Bhutan Pele-La, 3000m June

Description

Rhododendron kesangiae is a large-leaved rhododendron effectively endemic to Bhutan, where it is a conspicuous component of the temperate forest belt; GBIF records around 169 occurrences, the points from Canada, Sweden and Great Britain reflecting plants grown in specialist gardens and arboreta. It forms forests and thickets on cool, humid mountain slopes, typically between about 2700 and 3500 m, often in association with other big-leaved rhododendrons, magnolias and conifers. The illustrated collections from Yatong-La (2900 m, May), Nobding (2700 m, April) and Pele-La (3000 m, June) span its core range in central and western Bhutan and its spring-to-early-summer flowering.

It is a small tree or large shrub with stout branches and a rough, flaking bark. The large, elliptic to obovate leaves are leathery, dark green and somewhat rugose above, with the lower surface covered in a thin, silvery to pale fawn indumentum. The flowers are borne in dense, dome-shaped terminal trusses; the corolla is broadly campanulate, pale to deep pink or rose-purple, usually marked with a darker basal blotch, and contains numerous stamens around a stout ovary. The fruit is a woody, curved, dehiscent capsule releasing many small seeds.

Described only in 1991 by D.G. Long and Rushforth and named for Queen Kesang of Bhutan, R. kesangiae belongs to subsection Grandia (the large-leaved Himalayan rhododendrons), distinguished by leaf size, indumentum and flower colour. Its narrow, essentially Bhutanese distribution makes it a notable endemic of conservation interest, dependent on the continued integrity of mid-montane forest.

Author: D.G.Long & Rushforth · Sources: POWO (Kew), GBIF, Flora of Bhutan, The Genus Rhododendron (Cullen & Chamberlain), Rhododendrons of Bhutan