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Yunnan

Flowers of Yunnan — 68 species from the mountains of Yunnan in southwest China, part of the Hengduan and eastern Himalayan biodiversity hotspot renowned worldwide for its rhododendrons, primulas and gentians. This region is one of the great cradles of temperate plant diversity. Each species page provides a botanical description, distribution, habitat and flowering time with the original photograph.

Ranunculaceae

Aconitum nakaoi

by G & P Jürgens

Tamura

Bhutan2012 288
Bhutan Shele-La, 4100m September

Description

Aconitum nakaoi is a high-alpine monkshood distributed across the eastern Himalaya and the south-eastern Tibetan plateau margin, recorded from Bhutan, China (Xizang and adjacent Yunnan), Nepal and northern India. Its modest documentary record of around 21 georeferenced occurrences reflects both its restricted range and the difficulty of botanizing the steep upper screes and meadows it favours. The species inhabits open alpine turf, the margins of dwarf-shrub thickets and damp stony slopes, typically between about 3,800 and 4,500 m. The photographed plant from Shele-La in Bhutan at 4,100 m, flowering in September, is characteristic of its late-season anthesis in the cool, monsoon-influenced uplands where snowmelt and persistent humidity sustain the short growing season.

The plant is a perennial herb arising from small paired tuberous roots, with slender, often decumbent to ascending stems. The leaves are palmately divided into narrow, deeply incised segments, glabrous to thinly pubescent, the basal leaves long-petiolate and the cauline ones progressively reduced. The inflorescence is a lax few-flowered raceme bearing the zygomorphic, helmet-shaped flowers typical of the genus; the upper sepal forms a high, narrowly conical to galeate hood enclosing two long-clawed nectariferous petals, the colour ranging from violet-blue to dull purplish. The fruit is a cluster of several erect follicles releasing winged seeds.

Like all Aconitum, the species contains diterpenoid alkaloids and is highly toxic. It belongs to the taxonomically intricate Himalayan radiation of section Aconitum, where narrow endemics and clinal variation complicate species delimitation. Though not formally assessed as threatened, its narrow altitudinal band makes it sensitive to upward shifts of the treeline and to grazing pressure on alpine pastures.

Author: Tamura · Sources: POWO (Kew), Flora of China Vol. 6, Flora of Bhutan Vol. 1, GBIF, Tamura: Ranunculaceae in Die natürlichen Pflanzenfamilien

Orchideaceae

Aerides multiflora

by GP Jürgens

Roxb.

Sikkim2004 445 G776
Sikkim/India Tista-Valley 2000m May

Description

Aerides multiflora is an epiphytic orchid of the subtribe Aeridinae, native to the eastern Himalayas and extending into Southeast Asia. Its natural range encompasses Nepal, northeast India (Sikkim, Assam, Meghalaya, Arunachal Pradesh), Bhutan, Myanmar, Thailand, and southwest China (Yunnan). The species inhabits humid, semi-deciduous and evergreen forests at elevations of 200–2,000 m, typically growing on mossy tree trunks and branches in well-lit positions.

The plant produces stout, terete stems 20–40 cm long, clothed with distichous, coriaceous, strap-shaped leaves that are 15–25 cm long and unequally bilobed at the apex. The inflorescence is a densely many-flowered, pendent raceme 15–30 cm long, bearing 20–40 fragrant flowers. Individual flowers are 2–2.5 cm across, white to pale rose-pink with purple spots, the lip trilobed with a prominent forward-pointing spur. The mid-lobe is fleshy and tongue-shaped. Flowering occurs from April to June.

Aerides multiflora is valued in horticulture for its abundant, sweetly fragrant blooms. The species is under pressure from overcollection and habitat degradation across its range. Like all orchids, it is listed under CITES Appendix II, regulating international trade.

Author: Roxb. · Sources: POWO (Kew), Flora of Bhutan Vol. 3, GBIF, Pearce & Cribb: The Orchids of Bhutan (2002)

Apocynaceae

Alstonia sebusi

by GP Jürgens

(Van Heurck & Müll.Arg.) Monach.

Bh2008 497 P766
Bhutan Samtengang, 2200m April

Description

Alstonia sebusi (the accepted spelling being Alstonia sebusii) is a tree of montane forests in the eastern Himalaya and adjacent Southeast Asia, recorded from Bhutan, India, China (Yunnan), Myanmar and Japan, with about 50 georeferenced occurrences in GBIF. It occurs in broadleaved evergreen and mixed montane forest, typically on slopes within the warm- to cool-temperate belt. The specimen illustrated was photographed at Samtengang in Bhutan at about 2200 m in April; across its range it generally favours humid, well-drained forest soils where it grows as a canopy or sub-canopy tree.

The species is a small to medium-sized evergreen tree exuding milky latex when cut, as is characteristic of the genus. The leaves are arranged in whorls of three to several at the nodes, simple, entire, leathery and elliptic to oblong, with numerous closely parallel lateral veins. The flowers are small, white to cream, borne in terminal cymose clusters, with a salverform corolla whose tube bears overlapping lobes; the gynoecium consists of two carpels. The fruit comprises a pair of slender, pendulous follicles that split to release numerous flattened seeds bearing tufts of hair at each end, adapted for wind dispersal.

Alstonia (Apocynaceae, subfamily Rauvolfioideae) is a pantropical genus of latex-bearing trees rich in indole alkaloids, several of which have medicinal and pharmacological interest. The whorled leaves and paired follicles with comose seeds are diagnostic. Like other Alstonia species it provides soft, light timber locally used for carving and utility purposes. No major conservation threat is documented, though the species is dependent on the continued integrity of mid-elevation montane forest, which faces pressure from logging and land conversion in parts of its range.

Author: (Van Heurck & Müll.Arg.) Monach. · Sources: POWO (Kew), GBIF, Flora of China, Flora of Bhutan, Flora of Bhutan and Sikkim, Sidiyasa Revision of the Genus Alstonia

Orchideaceae

Anthogonium gracile

by GP Jürgens

Wall.

Bhutan2012 473
Bhutan Wangdi 2500m, September
Bhutan2012 474
Bhutan Wangdi 2500m, September

Description

Anthogonium gracile is a terrestrial orchid and the sole species in the monotypic genus Anthogonium. It is distributed from Nepal through northeast India (Sikkim, Darjeeling, Assam, Arunachal Pradesh), Bhutan, and Myanmar into Thailand, Indochina, and southwest China (Yunnan, Guangxi). The species occurs in open, grassy hillsides, pine forests, and degraded forest margins at elevations of 1,000–3,000 m, often in seasonally moist grassland.

The plant produces slender, reed-like stems 30–80 cm tall from underground tubers, with narrow, plicate, grass-like leaves arranged along the upper portion of the stem. The inflorescence is a lax, terminal raceme bearing 5–15 flowers that open successively. Flowers are 3–4 cm across, typically rose-pink to magenta, with a broad, spreading lip that is darker pink with a yellow callus of parallel lamellae. The column is slender and gently curved. Flowering in the Himalayas occurs from August to October.

Anthogonium gracile is taxonomically isolated within the Orchidaceae, though molecular phylogenetic analyses place it close to Calanthe and Phaius. Its preference for open, fire-maintained habitats suggests adaptation to seasonal burning regimes characteristic of Himalayan montane grasslands.

Author: Wall. · Sources: POWO (Kew), Flora of Bhutan Vol. 3, GBIF, Pearce & Cribb: The Orchids of Bhutan (2002)

Araceae

Arisaema griffithii

by GP Jürgens

Schott

Bhutan2014 360
Bhutan Tumching-La 3100m, May
Bhutan2014 830
Bhutan Thimphu 2450m, May
Sikkim2004 399 P681
Sikkim/India Lachung 3200m
Nepal 2001 104 ergebnis ergebnis
East-Nepal Gupka Pokhari 3050m, April

Description

Arisaema griffithii is an eastern Himalayan tuberous geophyte distributed through Nepal, Sikkim and Darjeeling in India, Bhutan, and into adjacent southern China (Xizang, Yunnan) and northern Myanmar, with georeferenced records also from Bangladesh. It is a plant of the cool temperate zone, growing in shaded moist forest, shrubberies, forest clearings and grassy slopes broadly between 2400 and 3600 m. The images document its altitudinal span, from Bhutan's Tumching-La at 3100 m and Thimphu at 2450 m flowering in May, to Lachung in Sikkim at 3200 m and Gupka Pokhari in east Nepal at 3050 m in April.

The plant arises from a depressed tuber and typically bears two trifoliolate leaves with broadly ovate to rhombic, acuminate leaflets, the lateral pair often oblique. The species is celebrated for its remarkable inflorescence: the spathe is large and deeply purple, conspicuously net-veined with pale reticulation, with the tube broadly funnel-shaped and the lamina arched and downturned, its margins recurved. The spadix appendix is exserted and elongated into a long, pendent whip-like flagellum. The plants are dioecious, with small unisexual flowers crowded at the base of the spadix, and the female inflorescence develops a cluster of red berries at maturity.

Within Araceae, A. griffithii belongs to section Sinarisaema and is one of the most distinctive members of the genus, named for William Griffith. Its drooping, intricately veined spathe lures fungus-gnat and small fly visitors into the inflorescence. Prized among specialist gardeners, it remains locally frequent and is not considered globally threatened, though vulnerable to habitat loss and tuber collection.

Author: Schott · Sources: POWO (Kew), GBIF, Flora of Bhutan, Flora of China, Gusman & Gusman 'The Genus Arisaema: A Monograph for Botanists and Nature Lovers'

Aristolochiaceae

Aristolochia griffithii

by GP Jürgens

Hook.f. & Thomson ex Duch.

Bhutan2014 454
Bhutan Tongsa 2000m, May
Bhutan2014 456
Bhutan Tongsa 2000m, May
Sikkim 2006 340 ergebnis
India West-Bengal, Tolung 2450m, May

Description

Aristolochia griffithii is an eastern Himalayan woody climber distributed through Nepal, Bhutan, north-east India and south-western China (Xizang, Yunnan), with scattered records extending into northern Myanmar and Thailand. In current taxonomic treatments the name returned as a synonym is referred to the accepted Aristolochia griffithii, under which the species is here treated. It grows in moist temperate broadleaved forest, climbing through trees and shrubs along forest margins and stream gorges, generally between about 1,800 and 3,000 m. The photographs from Tongsa in Bhutan at 2,000 m and from Tolung in West Bengal, India, at 2,450 m, both taken in May, document its late-spring flowering in this mid-montane forest belt.

It is a robust perennial liana with woody, twining stems and large, alternate, ovate-cordate leaves with deeply auriculate bases and entire margins. The flowers are solitary and exceptionally large and showy: the perianth is a strongly inflated, S-curved or globose tube expanding into a broad, spreading, conspicuously netted-veined limb mottled dark purple-brown and yellowish, terminating in a long tail-like appendage. The structure functions as a temporary insect trap, with inwardly directed hairs detaining pollinators (chiefly flies) until the anthers dehisce. The fruit is a pendulous, six-valved, septicidal capsule splitting basipetally into a parachute-like structure releasing flat winged seeds.

Aristolochia (Aristolochiaceae) is notable for its specialised kettle-trap pollination and for the aristolochic acids that render the tissues toxic; the genus includes important larval hosts for swallowtail butterflies. A. griffithii, among the largest-flowered Himalayan species, is prized horticulturally and is locally uncommon, its dependence on intact montane forest making it sensitive to habitat loss.

Author: Hook.f. & Thomson ex Duch. · Sources: POWO (Kew), Flora of China Vol. 5, Flora of Bhutan Vol. 1, GBIF, Hwang, Kelly & Gilbert: Aristolochiaceae in Flora of China

Asteraceae

Artemisia austroyunnanensis

by GP Jürgens

Ling & Y.R.Ling

Bhutan2015 310
Bhutan Trongsa 2000m, October

Description

Artemisia austroyunnanensis Ling & Y.R.Ling is a Sino-Himalayan and South-East Asian wormwood distributed from south-western China (notably southern Yunnan, whence the epithet) through Bhutan, India, Myanmar, Laos, Vietnam, Thailand and Japan, with about 70 georeferenced occurrences in GBIF. It grows on dry slopes, forest margins, roadsides, riverbanks and disturbed ground in warm-temperate to lower montane country. The plant recorded at Trongsa at 2000 m in October is consistent with its occurrence in the mid-elevation valleys of the Bhutan Himalaya, flowering toward the close of the growing season.

It is an aromatic perennial herb or subshrub with erect, ribbed and branching stems clothed, like the foliage, in a fine grey or whitish tomentum. The leaves are alternate, once or twice pinnatifid into narrow, often lobed segments, with the lower surface more densely tomentose than the upper. The minute, nodding capitula are numerous and crowded in elongate, paniculate inflorescences; each ovoid to subglobose head has imbricate, woolly-margined phyllaries and is disciform, with outer female florets surrounding inner bisexual disc florets, all wind-pollinated and lacking rays. The fruit is a small, smooth, ellipsoid cypsela without a pappus.

Artemisia is among the largest genera of Asteraceae, and A. austroyunnanensis sits within the subgenus Artemisia of anemophilous, capitulum-clustered species. Its delimitation rests on indumentum, leaf dissection and capitulum structure within a difficult species complex. A regionally distributed plant of disturbed and seasonally dry habitats, it is of no conservation concern.

Author: Ling & Y.R.Ling · Sources: POWO (Kew), GBIF, Flora of China, Flora of Bhutan, Ling taxonomic studies of Artemisia

Polygonaceae

Bistorta griffithii

by GP Jürgens

(Hook. f.) Grierson

BhutanPG2011 500
Bhutan Ludlow-Sherriff-Trail Mangde-Chu, 3950m July

Description

Bistorta griffithii (Hook. f.) Grierson is an alpine perennial herb of the eastern Himalaya, ranging through Bhutan, Sikkim and northern India into south-western China (Xizang, Yunnan) and northern Myanmar; the GBIF record of around 176 occurrences also includes herbarium-based citations from the United Kingdom and the United States. It is a plant of high alpine meadows, damp turf, rocky slopes and the upper margins of Rhododendron scrub, favouring cool, moisture-retentive soils kept wet by snowmelt and monsoon mist. The illustrated material was gathered along the Ludlow-Sherriff Trail at Mangde-Chu in central Bhutan at 3950 m in July, typical of the short midsummer flowering window in the upper alpine zone where this species reaches its display.

The plant arises from a short, thick, somewhat woody and contorted rhizome, producing erect, simple, unbranched stems. Basal leaves are long-petiolate with ovate to lanceolate or oblong blades, the margins entire and the lower surface often paler or thinly hairy; cauline leaves are few, smaller and shortly petiolate to sessile, subtended by membranous, tubular ochreae characteristic of the family. The inflorescence is a solitary, dense, terminal cylindrical to oblong spike of small flowers; perianth segments are five, white to pale pink, with eight stamens and a trifid style. As in many bistorts the lower flowers may be replaced by reddish bulbils. The fruit is a small, trigonous, dark brown shining achene enclosed by the persistent perianth.

Formerly placed in the broadly circumscribed genus Polygonum, this species is now treated in Bistorta on the basis of its perennial habit, unbranched flowering stems and dense terminal spikes. It is closely allied to other Himalayan bistorts such as B. macrophylla and B. vivipara, from which it is distinguished by leaf shape and inflorescence characters. Ecologically it contributes to the herbaceous turf grazed by livestock and wild ungulates, and the production of bulbils provides an effective means of vegetative propagation in the short, harsh alpine growing season. It has not been formally assessed for conservation but appears locally frequent within suitable habitat.

Author: (Hook. f.) Grierson · Sources: POWO (Kew), GBIF, Flora of Bhutan, Flora of China, Polygonaceae monograph (Hong & Steward)

Orchideaceae

Bulbophyllum griffithii

by GP Jürgens

Rchb.f.

Bhutan2012 444
Bhutan Wangdi 2500m, September
Bhutan2012 1171 Kopie
Bhutan Tashiyangtse 2000m, October

Description

Bulbophyllum griffithii is an epiphytic orchid distributed from the eastern Himalayas (Nepal, northeast India, Bhutan) through southwest China (Yunnan) to Taiwan. The species is named after William Griffith (1810–1845), the pioneering British botanist who collected extensively in Bhutan and northeast India. It occurs in cool, humid montane forests at elevations of 1,500–2,800 m, favouring mossy tree trunks in the cloud forest zone.

The pseudobulbs are ovoid to subglobose, 1.5–3 cm tall, widely spaced on a stout rhizome. Each bears a single, coriaceous, oblong-elliptic leaf 8–15 cm long. The inflorescence is an umbel-like, subglobose cluster of 5–12 flowers, carried on a slender peduncle 10–20 cm tall — a floral arrangement typical of section Cirrhopetalum. The flowers are about 2 cm across, pale yellow to greenish with purple-red stripes and spots. The dorsal sepal is erect, the lateral sepals elongated and twisted, and the lip is small, curved, and dark purple. Flowering occurs from August to October.

Within the complex taxonomy of Bulbophyllum section Cirrhopetalum, B. griffithii is recognised by its umbellate inflorescence with relatively few, medium-sized flowers and its distinctive striped pattern. GBIF records confirm a limited distribution centred on the eastern Himalayas and East Asia.

Author: Rchb.f. · Sources: POWO (Kew), Flora of Bhutan Vol. 3, GBIF, Pearce & Cribb: The Orchids of Bhutan (2002)

Orchideaceae

Bulbophyllum striatum

by GP Jürgens

Rchb.f.

Bhutan2012 1351
Bhutan Yankel 400m, October

Description

Bulbophyllum striatum is an epiphytic orchid confined to the eastern Himalayas and adjacent regions, with documented occurrences in northeast India (Sikkim, Assam, Meghalaya), Bhutan, Nepal, Bangladesh, and southwest China (Yunnan). It inhabits warm, humid subtropical and tropical forests at low to moderate elevations of 200–1,500 m — among the lower-altitude Bulbophyllum species in the Himalayan flora.

The pseudobulbs are ovoid, 2–3 cm tall, set at intervals on a stout, creeping rhizome. Each bears a single, oblong-lanceolate, coriaceous leaf 10–18 cm long. The inflorescence is an arching to pendent, laxly few-flowered raceme, 8–15 cm long, producing 3–8 flowers. The specific epithet 'striatum' (striped) refers to the conspicuous reddish-brown longitudinal striations on the sepals: flowers are 1.5–2 cm across, yellowish-green with prominent dark reddish-brown veining. The lip is dark purple, fleshy, curved, and mobile on the column foot. Flowering occurs from September to November.

The relatively low-altitude habitat of B. striatum at Yankel (400 m) in southern Bhutan reflects the warm, subtropical character of the Mo-Chu and lower Punatsangchu valleys, which harbour a distinct orchid flora adapted to high humidity and temperatures atypical for most of Bhutan.

Author: Rchb.f. · Sources: POWO (Kew), Flora of Bhutan Vol. 3, GBIF, Pearce & Cribb: The Orchids of Bhutan (2002)