Tag:

Sikkim

Flowers of Sikkim — 350 species from the Sikkim Himalaya in northeast India, a compact yet botanically extraordinary region that climbs from subtropical valleys to the alpine zone beneath Kangchenjunga. Sikkim is a classic centre of Himalayan plant diversity, celebrated for its rhododendrons, primulas, orchids and gentians. Each entry provides a botanical description, distribution, habitat and flowering season with the original field photograph.

Polygonaceae

Rheum acuminatum

by GP Jürgens

Hook. f. & Thomson

BhutanPG2011 778 01 01
Bhutan Chele-La, 3900m July
Sikkim2003 485 P673
Sikkim Lachung Valley 3500m August

Description

Rheum acuminatum is a stout perennial wild rhubarb of the eastern and central Himalaya, distributed through China, Nepal, India, Bhutan and Myanmar, with some 370 documented records. It is a plant of subalpine and alpine slopes, rocky meadows, open shrubberies and stream margins, generally growing between 3000 and 4300 m. The illustrated plants come from Chele-La in Bhutan at 3900 m in July and the Lachung Valley in Sikkim at 3500 m in August, spanning the high-summer flowering and fruiting period characteristic of the species at these elevations.

The plant arises from a thick woody rhizome and produces erect, often reddish, hollow stems up to a metre or more tall. The basal leaves are large, long-petiolate and broadly ovate-cordate with an acuminate apex giving the epithet, the blade more or less glabrous above and with prominent venation; an ochrea sheaths the stem at each node. The inflorescence is a tall, branched panicle bearing numerous small flowers with a coloured perianth of six segments, white to greenish or reddish. The fruit is a broadly winged triangular achene (a three-angled, three-winged nutlet) adapted to wind and water dispersal.

The genus Rheum reaches its richest diversity in the Himalaya and the Qinghai-Tibetan plateau, where high-altitude rhubarbs show striking adaptations to cold, exposed habitats. R. acuminatum lacks the inflated bracts of the alpine glasshouse rhubarbs but shares the family's ochreate, trigonous-fruited architecture. The rhizomes have a history of local medicinal use, and although the species is widespread and not threatened, related wild rhubarbs are subject to harvesting pressure across the region.

Author: Hook. f. & Thomson · Sources: POWO (Kew), GBIF, Flora of China, Flora of Bhutan, Annotated Checklist of the Flowering Plants of Nepal, Losina-Losinskaja revision of Rheum

Polygonaceae

Rheum nobile

by GP Jürgens

Hook. f. & Thomson

Sikkim2011 328
Sikkim Lada-La 4400m, June
Sikkim2003 309 G438
Sikkim Saniti-Lake 4300m August
Sikkim2003 310 W439
Sikkim Saniti-Lake 4300m August

Description

Rheum nobile, the Sikkim or noble rhubarb, is a spectacular high-alpine perennial of the eastern Himalaya, distributed from Nepal through Sikkim and northern India into Bhutan, Myanmar and south-western China, with around 220 occurrence records. It is a strict specialist of open alpine screes, moraines and rocky slopes, typically between about 4000 and 4800 m. The images derive from Sikkim at Lada-La (4400 m, June) and near Saniti Lake (4300 m, August), localities characteristic of the high, exposed scree habitat in which this iconic "glasshouse plant" grows.

The species forms a stout, columnar flowering spike to about 1-2 m, arising from a thick taproot. Its most striking feature is the dense, overlapping series of large, translucent, straw-coloured to pale yellow bracts that sheathe the entire inflorescence, hiding the small flowers within. The basal leaves are large, broadly ovate to orbicular and reddish-margined, forming a rosette. The numerous small flowers are greenish and inconspicuous, concealed beneath the bracts, and develop into small, three-winged nutlets (achenes) typical of the genus.

Rheum nobile (Polygonaceae) is a classic example of a Himalayan "greenhouse" or glasshouse plant: the translucent bracts trap solar heat and create a warm, sheltered microclimate that protects the developing flowers from cold, wind and intense ultraviolet radiation while attracting and harbouring specialist pollinating midges. This remarkable adaptation, much studied in plant ecophysiology, makes the species a celebrated model of high-altitude floral biology. Though localised, it is of least conservation concern, but its restriction to a narrow alpine belt makes it potentially vulnerable to climatic warming.

Author: Hook. f. & Thomson · Sources: POWO (Kew), GBIF, Flora of China, Flora of Bhutan, Annotated Checklist of the Flowering Plants of Nepal, Losina-Losinskaja monograph of Rheum

Crassulaceae

Rhodiola chrysanthemifolia

by GP Jürgens

(H. Lév.) Fu

Sikkim2003 396 G557
Sikkim Zemu Valley 3450m August
Sikkim2003 397 P558
Sikkim Zemu Valley 3450m August

Description

Rhodiola chrysanthemifolia is a high-altitude succulent of the Himalaya and adjacent China, recorded from China, Nepal, India and Bhutan with more than 630 georeferenced occurrences. It is a plant of alpine meadows, rocky slopes, cliff crevices and stabilised screes, typically growing well above the treeline. The population photographed in the Zemu Valley of northern Sikkim at about 3450 m in August represents its characteristic alpine habitat, flowering and fruiting in late summer on cool, well-drained, often rocky substrates exposed to intense montane conditions.

The species is a glabrous perennial arising from a stout, woody, often branched caudex topped by a persistent rootstock. The annual flowering stems bear numerous alternate, fleshy leaves that are toothed to pinnately incised, the dissection recalling the foliage of Chrysanthemum and reflected in the epithet chrysanthemifolia. The flowers are grouped in dense terminal cymes; as in Rhodiola the plant is typically dioecious, with the small four- to five-merous flowers bearing distinct sepals and yellow to greenish-yellow or reddish-tinged petals. The fruit comprises erect, beaked follicles that split along the inner suture to release the small seeds.

Rhodiola, segregated from Sedum on the basis of its perennial caudex, dioecy and basally connate carpels, is a circumboreal and alpine Asian genus of considerable interest for its adaptogenic secondary chemistry. Several Himalayan congeners are intensively harvested for medicinal roots, placing wild populations under pressure, although R. chrysanthemifolia itself remains widespread and locally common across the high Himalaya and is not presently regarded as threatened.

Author: (H. Lév.) Fu · Sources: POWO (Kew), GBIF, Flora of Nepal, Flora of China, Flora of Bhutan, Ohba's studies of Himalayan Crassulaceae

Crassulaceae

Rhodiola himalensis

by GP Jürgens

(D. Don) Fu

Garw 2005 349 ergebnis
Garhwal Pataathi 4150 m, September
Bh09 132 P231
Bhutan Jimilangtso 4050m, June
Sikkim2011 292
Sikkim Lada-La 4000m, June

Description

Rhodiola himalensis is a characteristic high-alpine succulent of the Himalaya and adjacent Sino-Himalayan mountains, documented by some 562 georeferenced records from Nepal (NP), China (CN), India (IN), Bhutan (BT), Pakistan (PK) and Mongolia (MN), with a peripheral record in Japan (JP). It occupies the alpine zone, broadly between 3500 and 5000 m, on rocky slopes, screes, grassy alpine meadows, stream banks and moist ledges. The collections cited from Pataathi in Garhwal at 4150 m, Jimilangtso in Bhutan at about 4050 m and Lada-La in Sikkim at 4000 m, flowering between June and September, illustrate its broad occurrence across the central and eastern Himalaya at consistently high elevation.

It is a perennial herb arising from a stout, scaly, branched caudex topped by a fleshy rootstock. The flowering stems are erect to ascending and clothed with numerous, spreading, flat, sessile leaves; these are oblong-lanceolate to elliptic, fleshy, entire to minutely toothed, and often somewhat glaucous. The species is dioecious, the small flowers gathered into a dense terminal corymb; the staminate flowers are dark red to purplish with four parts and eight stamens, while the pistillate flowers develop into clusters of erect, dark red to purplish follicles bearing numerous minute seeds. The dark, often blackish-purple inflorescence colour is a notable field character.

Rhodiola (Crassulaceae), segregated from Sedum, comprises cold-adapted, perennating CAM succulents whose persistent woody caudex enables survival of harsh alpine winters and short growing seasons. R. himalensis, like several congeners, is gathered for use in Tibetan and Himalayan traditional medicine, contributing to localised harvesting pressure. The species remains widespread and is not formally threatened, though slow regeneration makes high-altitude Rhodiola populations vulnerable to sustained overcollection.

Author: (D. Don) Fu · Sources: POWO (Kew), GBIF, Flora of China, Flora of Bhutan, Annotated Checklist of the Flowering Plants of Nepal, Ohba monographic studies of Himalayan Crassulaceae (Rhodiola)

Crassulaceae

Rhodiola hobsonii

by G & P Jürgens

(Prain ex Raym.-Hamet) S.H.Fu

Bhutan2012 88
Bhutan Chele La 4150m, September

Description

Rhodiola hobsonii is an alpine succulent perennial of the eastern Himalaya and adjacent southwestern China, recorded from Bhutan, northern India (Sikkim, Arunachal), Nepal and the Chinese provinces of Xizang and Yunnan; GBIF holds about 101 records. It inhabits open stony slopes, gravelly screes, rock crevices and short alpine turf, generally between about 3800 and 5000 m, enduring intense insolation and a brief growing season. The photographed plant was collected at the Chele La pass in western Bhutan at around 4150 m in September, on the well-drained, frost-disturbed substrates it occupies near the upper limit of vascular plant growth.

The plant arises from a stout, woody, persistent caudex crowned by the scaly remains of old leaf bases, from which several short, fleshy, erect or ascending flowering stems develop. The leaves are alternate, sessile, succulent, oblong to obovate, entire or sparingly toothed toward the apex, and rather densely set. The inflorescence is a compact terminal cyme; the species is dioecious, the flowers four- or five-merous and dull purplish-red, the petals narrow. The fruit comprises several erect follicles that split to release minute seeds.

Rhodiola (Crassulaceae) is a large genus of cold alpine and arctic regions, segregated from Sedum by its perennial woody caudex and predominantly dioecious flowers. R. hobsonii belongs to the diverse Sino-Himalayan assemblage of the genus, many members of which are rich in rosavins and salidroside and used in regional traditional medicine. Restricted to high elevations, it is naturally localised but not currently assessed as threatened, though such cushion-zone specialists are vulnerable to warming.

Author: (Prain ex Raym.-Hamet) S.H.Fu · Sources: POWO (Kew), GBIF, Flora of China Vol. 8, Flora of Bhutan Vol. 1, Flora of Nepal, Flora of Pakistan, Ohba monograph of Himalayan Sedoideae and Rhodiola

Crassulaceae

Rhodiola sherriffii

by GP Jürgens

H. Ohba

BhutanPG2011 518
Bhutan Dem-Tso, 4500m June

Description

Rhodiola sherriffii is a rare, narrowly distributed alpine succulent of the Eastern Himalaya, recorded from Bhutan, the adjacent Indian states (Sikkim, Arunachal Pradesh), Nepal and southern Tibet (China); GBIF documents only about 20 occurrences, underscoring its restricted range and the relative inaccessibility of its habitat. It is a plant of the high alpine zone, typically growing above 4000 m, as illustrated near Dem-Tso in Bhutan at 4500 m, where it occupies open stony slopes, glacial moraine, rock crevices and gravelly fellfield. Like other members of the genus it tolerates intense insolation, frost and a short growing season, flowering in early summer (June) as snow recedes.

It is a small, glabrous, glaucous perennial herb arising from a thick, woody, scaly caudex and rootstock. Several short, erect or ascending flowering stems bear numerous fleshy, succulent leaves that are entire to obscurely toothed, sessile, oblong to obovate and crowded along the stem. The inflorescence is a dense, terminal, corymbose to capitate cyme. The flowers are usually unisexual (the genus being dioecious), 4-5-merous, with petals and sepals that are commonly dark red to purplish; the carpels are erect, maturing into small, erect follicles containing numerous minute seeds.

Named for the plant collector George Sherriff, who with Frank Ludlow explored Bhutan and southeastern Tibet, the species belongs to a Himalayan complex of red-flowered Rhodiola allied to R. bupleuroides and R. coccinea. The genus Rhodiola was segregated from Sedum on the basis of its perennial scaly caudex and predominantly dioecious flowers. Many Rhodiola species accumulate medicinally valued secondary metabolites and are harvested as adaptogens, exposing the genus to collection pressure. Given its small population number and high-elevation habitat, R. sherriffii is potentially vulnerable to climate-driven habitat contraction, though it has not been formally assessed.

Author: H. Ohba · Sources: POWO (Kew), GBIF, Flora of Bhutan, Flora of China, Ohba's monograph of Himalayan Crassulaceae (Rhodiola)

Crassulaceae

Rhodiola wallichiana

by GP Jürgens

(Hook.) Fu

Nepal 99 261 ergebnis
Nepal Kalomura 4000m, July
Sikkim2003 395 G556
Sikkim Zemu Valley 3400m August
Sikkim2003 480 P666
Sikkim Zemu Valley 3400m August

Description

Rhodiola wallichiana is a high-elevation succulent perennial of the Himalaya and Tibetan margins, native from Nepal and the Indian Himalaya through Sikkim and Bhutan into southern China, Pakistan and Afghanistan; the many European and North American GBIF records reflect cultivated and herbarium material rather than wild occurrence. It grows in the alpine and upper subalpine zone, on rocky slopes, cliff ledges, moraines and among boulders. The cited collections from Kalomura in Nepal at about 4000 m in July and the Zemu valley in Sikkim at 3400 m in August place it firmly in the summer-flowering high-mountain flora.

The plant arises from a stout, branched, woody caudex (rootstock) bearing several erect or ascending leafy flowering stems. The leaves are alternate, sessile, fleshy, linear-lanceolate to oblong, flat, with entire or finely toothed margins, densely clothing the stems. The inflorescence is a terminal corymbose cyme of numerous small flowers. The species is functionally dioecious; the flowers are typically four- to five-merous, with greenish-yellow to reddish petals, the staminate flowers bearing stamens twice the number of petals, and the pistillate flowers developing several erect follicles that ripen reddish and split to shed minute seeds.

Rhodiola, segregated from Sedum, comprises the rosette- and caudex-forming stonecrops of cold northern and montane regions. Like its relatives the genus accumulates protective metabolites, and several species are harvested as adaptogenic medicinals, placing wild Himalayan populations under collection pressure. Adapted to short alpine summers, intense radiation and cold, R. wallichiana is locally frequent within its range and not currently assessed as globally threatened.

Author: (Hook.) Fu · Sources: POWO (Kew), GBIF, Flora of China, Flora of Bhutan, Ohba's monographic studies of Himalayan Crassulaceae (Rhodiola)

Ericaceae

Rhododendron aeruginosum

by GP Jürgens

Hook.f.

Sikkim2011 125
Sikkim Chopta-valley 4100m, June
Sikkim2011 349
Sikkim Lada-La 4000m, June
Sikkim2011 362
Sikkim Lada-La 4000m, June
Sikkim2003 422 P587 2
Sikkim Chopta Valley 3400m August

Description

Rhododendron aeruginosum is an evergreen shrub of the eastern Himalaya, native to Sikkim and the rest of India, Bhutan, Nepal and adjacent China. Its roughly 106 georeferenced records describe a narrowly distributed high-montane taxon. It grows in the upper subalpine to lower alpine belt, forming dense thickets on open slopes, ridges and rocky pasture above the treeline at roughly 3300-4400 m. The Sikkim collections noted above, from the Chopta valley at 3400-4100 m and Lada-La at 4000 m in June and August, are characteristic of its windswept, high-elevation habitat at and above the krummholz zone.

It is a compact shrub whose striking young leaves are covered with a thick, glaucous blue-green to verdigris waxy bloom, the epithet aeruginosum meaning "rust- or copper-coloured." The mature leaves are elliptic to oblong, leathery and coated beneath with a dense fawn to rufous indumentum. The flowers are borne in compact terminal trusses and are broadly campanulate, pale rose to white often flushed pink and spotted within, with ten stamens and a glabrous ovary. The fruit is a curved, woody, septicidal capsule releasing many small seeds.

Rhododendron aeruginosum is closely allied to R. campanulatum, under which name it has often been treated as a high-altitude variant or subspecies and to which the original web placement refers, the two distinguished chiefly by the glaucous juvenile foliage and dwarfer, more exposed habit of aeruginosum. It belongs to the large elepidote subgenus Hymenanthes and subsection Campanulata. Pollination is by bumblebees and other alpine insects. Its restricted high-altitude range makes it locally vulnerable to grazing, fire and the upslope compression of alpine shrubland under a warming climate.

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

Ericaceae

Rhododendron anthopogon

by GP Jürgens

D. Don

Sikkim2011 95
Sikkim Chopra-valley 4200m, June
Sikkim2011 96
Sikkim Chopra-valley 4200m, June

Description

Rhododendron anthopogon is a dwarf, aromatic alpine shrub of the Himalaya, recorded in GBIF (around 1052 occurrences) from Nepal, India, China, Bhutan and Pakistan. It dominates open alpine slopes, moorland, rocky ridges and the upper limit of shrub vegetation, generally between 3000 and 5000 m, often forming extensive low thickets above the tree line together with junipers and other dwarf rhododendrons. The photographed population in the Chopra valley of Sikkim at 4200 m in June represents this typical high-alpine, exposed habitat, where it flowers as snow recedes in early summer.

It is a low, much-branched, evergreen shrub usually under 1 m tall, with young shoots bearing peltate scales. The small, alternate, leathery leaves are elliptic to ovate, aromatic when crushed, densely brown-scaly (lepidote) beneath and with a slightly recurved margin. The flowers are borne in compact terminal clusters; each has a narrowly tubular corolla, white to pale pink or cream, with a short spreading limb of five lobes and a hairy throat, and characteristically only five to ten included stamens. The fruit is a small, scaly, dehiscent capsule releasing minute seeds.

Rhododendron anthopogon is the type of subsection Pogonanthum within section Rhododendron (the lepidote rhododendrons), a group of aromatic, scaly, tubular-flowered dwarf alpines centred on the Himalaya and western China. Its foliage is rich in essential oils and is harvested as the incense and herbal medicine sunpati. Widespread and often locally abundant across the high Himalaya, it is assessed as Least Concern, functioning as a key soil-stabilising and structural component of alpine heath ecosystems.

Author: D. Don · Sources: POWO (Kew), GBIF, Flora of Bhutan, The Rhododendrons of Sikkim-Himalaya, Annotated Checklist of the Flowering Plants of Nepal, Cullen revision of lepidote Rhododendron

Ericaceae

Rhododendron arboreum subst. cinnamomeum

by GP Jürgens

(Wall. ex G. Don) Tagg.

Bhutan2014 370
Bhutan Jakar 3900m, May
Nepal 97 225 G465
Nepal Thudam 3850m April
Nepal 1994 286 ergebnis
Ost-Nepal Milka-Danda 3100m May 

Description

Rhododendron arboreum var. cinnamomeum (Wall. ex G. Don) Tagg is a high-elevation race of the widespread tree rhododendron distributed across the eastern and central Himalaya, with records concentrated in Nepal, Bhutan, Sikkim and adjacent China. It occupies the upper temperate to subalpine belt, typically between 3000 and 3900 m, forming dense thickets and the canopy of mossy fir-rhododendron forest. The photographed populations span this range, from Bhutan's Jakar valley at 3900 m and Nepal's remote Thudam at 3850 m to the Milka-Danda ridge of eastern Nepal at 3100 m, all flowering between April and May as the snow retreats. It thrives on acidic, humus-rich soils on cool, north-facing slopes with high atmospheric humidity.

This variety is a shrub or small gnarled tree distinguished from typical R. arboreum by the dense, persistent indumentum on the lower leaf surface. The leathery, oblong-lanceolate to oblanceolate leaves are dark green and rugose above, while beneath they bear a thick, felted, cinnamon- to rust-brown tomentum (the source of the epithet cinnamomeum). Flowers are borne in compact, rounded terminal trusses; the campanulate corolla, ranging from deep blood-red through pink to occasional white, has dark nectar pouches and conspicuous spotting on the upper lobes. The fruit is a woody, curved, dehiscent capsule releasing numerous minute winged seeds.

Taxonomically the taxon sits within the polymorphic R. arboreum complex (subgenus Hymenanthes), where the white-flowered, heavily indumented high-altitude plants have at times been treated as a distinct subspecies. The species is the national flower of Nepal and a foundational element of Himalayan cloud-forest ecosystems, supporting sunbirds and other nectarivores as pollinators. While not globally threatened, upper-montane var. cinnamomeum populations are sensitive to grazing, fuelwood collection and climate-driven treeline shifts.

Author: (Wall. ex G. Don) Tagg. · Sources: POWO (Kew), GBIF, Flora of Bhutan, Flora of China, The Genus Rhododendron (Cox & Cox), Rhododendrons of the Himalaya (Tagg)