Author

GP Jürgens

Araceae

Arisaema utile

by GP Jürgens

Hook.f. ex Engl.

Sikkim2011 221
Sikkim, Yungthang 3350m, June
Sikkim2011 222
Sikkim, Yungthang 3350m, June
Sikkim2004 430 P746
Sikkim/India Lachung 3200m

Description

Arisaema utile is a tuberous geophyte of the Himalaya and adjacent ranges, recorded by GBIF in some 84 occurrences from China (Tibet), India, Pakistan, Nepal, Bhutan and Myanmar. It is a plant of the subalpine to lower alpine zone, occupying shrubberies, Rhododendron and conifer forest margins, moist meadows and stony slopes broadly between 3000 and 4300 m. The illustrated plants were found in Sikkim at Yungthang (3350 m, June) and Lachung (3200 m), where the species emerges and flowers shortly after snowmelt on cool, humus-rich ground at the upper limit of woody vegetation.

The plant arises from a depressed-globose tuber and typically bears a single trifoliolate leaf, the three leaflets broadly elliptic and often glaucous beneath, the whole sometimes purple-flushed. The inflorescence is a spadix subtended by a spathe whose tube is striped green and dark purple and whose limb is hooded and acuminate, frequently produced into a long filiform tip. The spadix appendix is slender and tail-like, exserted from the spathe mouth. As in the genus, the plant is paradioecious, individual tubers bearing male or female flowers according to size and vigour; pollinated female spadices ripen into a cylindrical infructescence of bright red berries.

Arisaema (Araceae, tribe Areae) is a large genus centred on the Sino-Himalayan region, and A. utile belongs to a Himalayan group characterised by a long-tailed spathe and trifoliolate leaf. GBIF treats the name as accepted. Sex expression shifts with resource status, an adaptation to harsh montane conditions; although collected for traditional use, the species remains locally frequent within its altitudinal band.

Author: Hook.f. ex Engl. · Sources: POWO (Kew), GBIF, Flora of China, Flora of Bhutan, Gusman monograph The Genus Arisaema

Araceae

Arisaema vexillatum

by GP Jürgens

Hara & H.Ohashi

Nepal 97 249 P520
Nepal below Thudam 3450m, May

Description

Arisaema vexillatum is a narrowly distributed tuberous aroid of the eastern Himalaya and adjacent China, known from only China and Nepal with a sparse total of about 11 georeferenced records, reflecting both genuine rarity and limited collecting. It grows in cool-temperate to subalpine forest and shrubberies, in moist, humus-rich soils sheltered by rhododendron and conifer cover. The type material and the photographed plant come from the upper Arun drainage of eastern Nepal below Thudam at around 3450 m, flowering in May as the snow recedes, indicating a strongly montane ecology dependent on persistent soil moisture.

The plant arises from a depressed, subglobose tuber and produces typically a single leaf with a long sheathing petiole. The leaf blade is pedately divided into several oblong-lanceolate, acuminate leaflets arranged in a radiate fashion. The inflorescence is a spathe enclosing the spadix, the spathe tube cylindrical and the limb arching forward; the spadix appendix is slender and the plant is generally monoecious-dioecious depending on tuber size, a sex-lability typical of the genus. The fruiting spadix develops into a dense, club-shaped syncarp of bright red, few-seeded berries.

Arisaema vexillatum belongs to a difficult complex of eastern Himalayan species and was described by Hara and H. Ohashi from Nepalese collections. Like most Arisaema it depends on fungus-gnat and small-fly visitors trapped within the spathe for pollination. Its limited known range and montane habitat suggest vulnerability to habitat disturbance, though its conservation status remains formally unassessed and additional fieldwork would likely clarify its true distribution.

Author: Hara & H.Ohashi · Sources: POWO (Kew), GBIF, Flora of China, Annotated Checklist of the Flowering Plants of Nepal, Gusman & Gusman The Genus Arisaema

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

Moraceae

Artocarpus heterophyllus

by GP Jürgens

Lam.

Nepal 97 561 P1094
Nepal Sabha-Khola 550m May
Nepal 97 563 P1096
Nepal Sabha-Khola 550m May
Nepal 97 562 P1095
Nepal Sabha-Khola 550m, May
Nepal 1994 44 ergebnis
Ost-Nepal Simbhuwa Kola 
1250m, April

Description

Artocarpus heterophyllus Lam., the jackfruit, is a large evergreen tree believed to be native to the Western Ghats and rainforests of the Indian subcontinent, now cultivated and naturalised throughout the tropics. The extensive GBIF record spans India, Sri Lanka, Bangladesh, China, much of Southeast Asia and Malesia, as well as tropical Africa, the Mascarenes, Brazil and the Pacific, reflecting its pantropical cultivation. In the Himalayan foothills it is grown in warm, humid lowland and lower hill country; the records from the Sabha Khola in Nepal at 550 m in May and the Simbhuwa Khola in east Nepal at 1,250 m in April document its cultivation in subtropical river valleys near the upper limit of its tolerance.

The tree reaches 10–25 m, with a dense, spreading crown and copious white latex in all parts. The alternate, leathery, glossy leaves are obovate to elliptic and entire in adult foliage, although juvenile and coppice leaves may be lobed, accounting for the epithet heterophyllus. The species is monoecious, with minute flowers densely aggregated on separate male and female inflorescences. After pollination the female heads develop into the immense, syncarpous compound fruit, the largest borne by any tree, which may exceed 30 kg; it is oblong, green, covered in conical, hexagonal protuberances, and contains numerous seeds embedded in sweet, aromatic, edible perianth flesh and surrounded by fibrous tissue, the whole borne cauliflorously on the trunk and main branches.

A member of Moraceae, the breadfruit and fig family, jackfruit is among the most important food trees of the humid tropics, the fruit eaten ripe or as a vegetable and the seeds cooked, while the durable, yellow timber and a dye from the heartwood are also valued. As an ancient cultigen of long human domestication it has no conservation concern, but its biogeography illustrates the role of human dispersal in shaping pantropical crop distributions.

Author: Lam. · Sources: POWO (Kew), GBIF, Flora of China Vol. 5, Flora of Nepal, Jarrett: Studies in Artocarpus and Allied Genera (Journal of the Arnold Arboretum)

Orchideaceae

Arundina graminifolia

by GP Jürgens

(D.Don) Hochr.

Bhutan2012 523
Bhutan Wangdi Phodrang 2400m, September
Bhutan2015 247
Bhutan Zhemgang 1000m, October

Description

Arundina graminifolia, commonly known as the bamboo orchid, is a robust terrestrial species with a remarkably wide distribution from the Himalayas (Nepal, India, Bhutan) through Southeast Asia to southern China, the Malay Archipelago, and the Pacific Islands. It has become naturalised in parts of tropical America, Hawaii, and the Caribbean. In the Himalayas, it grows on exposed banks, road cuttings, landslide scars, and open grasslands at 200–2,800 m elevation, favoring well-drained, acidic soils with good light exposure.

The plant forms dense clumps of erect, reed-like stems 60–150 cm tall, bearing linear-lanceolate, grass-like leaves 10–20 cm long that are arranged distichously. Flowers are produced terminally, 5–8 cm across, resembling small Cattleya blooms: the sepals and petals are white to pale pink, while the lip is deep rose-purple with a tubular base and a broad, ruffled apical lobe. Flowers open successively over an extended period, with individual blooms lasting only 2–3 days. In the eastern Himalayas, flowering peaks from August to November.

Arundina graminifolia is one of very few orchids that thrives as a pioneer species on disturbed ground. Its wide ecological amplitude and capacity for rapid colonisation are facilitated by its production of numerous wind-dispersed seeds. The species exhibits considerable morphological variation across its vast range, and several subspecific taxa have been proposed.

Author: (D.Don) Hochr. · Sources: POWO (Kew), Flora of Bhutan Vol. 3, GBIF, Seidenfaden: The Orchids of Indochina (1992)

Apocynaceae

Asclepias curassavica

by GP Jürgens

L.

Bhutan2014 65
Bhutan Trashigang 1300m, May
Bhutan2014 66
Bhutan Trashigang 1300m, May

Description

Asclepias curassavica, the scarlet or tropical milkweed, is native to tropical America but is now a pantropical weed of cultivation and waste ground, reflected in its more than 40,000 GBIF occurrences spanning Mexico, the United States, Central America and the Caribbean, Brazil and Andean South America, and introduced populations across China, Taiwan, India and Australia. In the Himalayan region it is naturalised at lower warm elevations along roadsides, field margins and disturbed slopes, as shown by the Bhutanese record from Trashigang at 1300 m in May, well within its preferred frost-free montane-foothill zone.

It is an erect perennial herb or subshrub 0.5-1 m tall with slender, sparingly branched stems exuding milky latex when cut. The leaves are opposite, lanceolate to narrowly elliptic, short-petioled and acuminate. The flowers are borne in terminal and axillary umbel-like cymes; each has five reflexed red to orange-red corolla lobes and a contrasting yellow to orange central corona (gynostegial hoods with incurved horns), the whole forming the characteristic asclepiad pollinarium-bearing structure. The fruit is a slender erect follicle splitting to release numerous flat seeds bearing a silky coma for wind dispersal.

A member of the milkweed subfamily Asclepiadoideae (now placed in Apocynaceae), it is rich in cardenolide toxins and serves as a host for monarch and other danaine butterflies. Widely grown ornamentally and for traditional medicine, it spreads readily and behaves as an invasive in many warm regions; it is of no conservation concern and is instead frequently managed as a weed.

Author: L. · Sources: POWO (Kew), GBIF, Flora of China, Flora of Bhutan, Flora of North America, Woodson monograph of Asclepias

Asteraceae

Aster ageratoides

by GP Jürgens

Turcz.

Bhutan2012 866
Bhutan Jakar 2200m, October

Description

Aster ageratoides Turcz. is a widespread and variable East Asian aster ranging through China, Japan, Korea, Taiwan, Russia, Vietnam, Thailand, Nepal, India and Bhutan, with more than 14,000 georeferenced occurrences in GBIF and an increasing presence as an introduction in parts of Europe and North America. It occupies forest margins, grassy slopes, thickets, streamsides and roadside banks across a broad altitudinal range. The plant recorded at Jakar at 2200 m in October is typical of its late-season flowering in the mid-elevation temperate zone of the Bhutan Himalaya.

It is a rhizomatous perennial herb with erect, often branched stems that are scabrid to pubescent. The leaves are alternate, ovate-lanceolate to elliptic, with a serrate to coarsely toothed margin, three more or less prominent main veins, and a rough surface; the lower leaves are petiolate and the upper ones become sessile. The capitula are arranged in a lax corymbose array; each radiate head has an involucre of imbricate, graduated phyllaries, a single series of white to pale violet or purplish ray florets, and numerous yellow disc florets. The fruit is a compressed, hairy cypsela crowned by a pappus of reddish bristles.

A.ageratoides is notoriously polymorphic, and numerous subspecies, varieties and forms have been described across its range based on leaf shape, indumentum and head size. Modern molecular systematics has reorganised the broad genus Aster, but this Asian species is retained in Aster sensu stricto. Common and ecologically flexible, it is of no conservation concern.

Author: Turcz. · Sources: POWO (Kew), GBIF, Flora of China, Flora of Bhutan, Nesom systematic studies of Astereae

Asteraceae

Aster albescens

by GP Jürgens

(DC.) Wall. ex Hand.-Mazz.

Sikkim2003 379 G532
Sikkim Tista valley 3600m August
Garw 2005 38 ergebnis ergebnis
India Garhwal Valley of flowers 3200m, September

Description

Aster albescens is a variable shrubby aster widespread through the Himalaya and into China, Myanmar and East Asia, with 1,298 GBIF occurrences from China, Nepal, India, Bhutan, Japan, Korea and Myanmar. It grows on forest margins, open slopes, shrubberies and stream banks in the upper temperate to subalpine zone, broadly between about 2000 and 4000 m. The images derive from Sikkim's Tista valley at 3600 m in August and from the Valley of Flowers in Garhwal, India, at 3200 m in September, monsoon-watered slopes where this late-summer flowerer is a frequent component of the shrub layer.

Unusually for an aster, it is a woody shrub or subshrub up to about 1-2 m, with erect, branched, often whitish-tomentose stems. The leaves are alternate, ovate to lanceolate or elliptic, shortly petiolate, with serrate to entire margins and a characteristically pale, white-felted lower surface (whence albescens), the upper surface greener and thinly hairy. The capitula are numerous and small, arranged in dense terminal corymbose panicles; each head bears few short white, pinkish or pale purple ray florets around a disc of yellow florets. The cypselae are compressed and pubescent, with a pappus of reddish to brownish barbellate bristles.

Described as Diplopappus albescens by de Candolle and transferred to Aster by Wallich ex Handel-Mazzetti, the species is highly polymorphic and has spawned numerous infraspecific taxa across its range. Its shrubby habit places it among the woody Himalayan-Sino asters retained in Aster sensu lato. Common and ecologically resilient across a broad area, it is not considered threatened.

Author: (DC.) Wall. ex Hand.-Mazz. · Sources: POWO (Kew), GBIF, Flora of Bhutan, Flora of China, Flowers of the Himalaya (Polunin & Stainton), Asteraceae of the Himalaya

Asteraceae

Aster diplostephioides

by GP Jürgens

(DC.) Benth. ex C.B.Clarke

Bhutan2012 248
Bhutan Haar-Valley, 4000m September

Description

Aster diplostephioides is a striking alpine daisy of the high Himalaya and Tibetan borderlands, recorded by GBIF (322 occurrences) from China, India, Nepal and Bhutan. It inhabits open alpine meadows, grassy slopes, stony pastures and stream margins, typically between about 3000 and 4500 m. The plant illustrated was photographed in Bhutan's Haa (Haar) Valley at 4000 m in September, a high subalpine-to-alpine zone where short summers and intense insolation favour large-headed, single-flowered composites that bloom into the post-monsoon period.

It is a perennial herb arising from a stout, woody rhizome, producing erect, simple, glandular-hairy stems usually to 30-50 cm. The leaves are alternate, oblanceolate to spathulate, entire, somewhat clasping above, and clothed in spreading hairs. Each stem bears a single large, solitary capitulum subtended by herbaceous, often purple-tinged phyllaries in two or three rows. The numerous narrow ray florets are blue to violet-purple and conspicuously long, surrounding a central disc of yellow florets that turns orange-purple with age. The cypselae are flattened and hairy, bearing a pappus of unequal barbellate bristles.

The species was described as Heterochaeta diplostephioides by de Candolle and transferred to Aster by Bentham ex C.B. Clarke. Although molecular work has redistributed much of the former broad Aster, the high-elevation Himalayan asters such as this remain referable to Aster sensu stricto. Its conspicuous solitary heads make it a notable component of Himalayan alpine meadows. It is widespread within its montane range and not regarded as threatened, though alpine habitats face pressure from grazing intensification and climate warming.

Author: (DC.) Benth. ex C.B.Clarke · Sources: POWO (Kew), GBIF, Flora of Bhutan, Flora of China, Flowers of the Himalaya (Polunin & Stainton), Asteraceae of the Himalaya