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Summer

Sapindaceae

Acer caudatum

by G & P Jürgens

Wall.

BhutanPG2011 59
Bhutan Jakar, 2100m June
BhutanPG2011 60
Bhutan Jakar, 2100m June

Description

Acer caudatum is a deciduous maple of the Himalaya and the mountains of China, distributed through China, Nepal, India, Bhutan, Myanmar, Afghanistan and into Russia, with over two thousand recorded occurrences across this broad range. It is a tree of moist temperate and subalpine forest, growing in mixed broad-leaved and conifer woodland, along ravines and on cool shaded slopes on humus-rich soils. In Bhutan it occurs in the middle montane belt, as illustrated by the collection near Jakar in the Bumthang region at about 2100 m in June, when the trees are in full leaf and flower.

The species is a small to medium-sized tree with smooth greyish bark and slender branchlets. The leaves are opposite, long-petiolate and orbicular in outline, palmately five- to seven-lobed with the lobes ovate-acuminate and the margins sharply and doubly serrate, often softly hairy on the veins beneath. The inflorescence is an erect terminal raceme or narrow panicle bearing numerous small yellowish-green flowers. The fruit is the typical maple double samara, the two nutlets each bearing a membranous wing, the wings spreading at a wide to nearly horizontal angle to enable anemochorous dispersal of the seeds.

Acer caudatum, described by Wallich and now placed in Sapindaceae following the merger of the former Aceraceae, is a variable species classified within section Spicata, the group of maples with erect spike-like inflorescences. Several geographical varieties have been recognised across its range, reflecting its wide montane distribution. The species is a normal component of Himalayan temperate forest and is not threatened, contributing to autumn colour and, through its winged fruits, to the regeneration dynamics of mid-elevation woodland.

Author: Wall. · Sources: POWO (Kew), GBIF, Flora of China Vol. 11, Flora of Bhutan Vol. 2, Flora of Nepal, Flora of Pakistan, van Gelderen et al. Maples of the World

Ranunculaceae

Aconitum hookeri

by GP Jürgens

Stapf

Sikkim2003 249 P343
Sikkim Dzongri 4300m, August
Sikkim2003 251 G345
Sikkim Dzongri 4300m 08.2003
Sikkim2003 250 G344
Sikkim Dzongri 4200m, August

Description

Aconitum hookeri is an alpine perennial of the eastern Himalaya, recorded from Nepal, China and India (NP, CN, IN, with further records), with around 96 documented occurrences. It inhabits open alpine meadows, grassy slopes, stony pastures and the margins of dwarf scrub in the high alpine zone, generally between about 4000 and 4800 m. The collections cited were all made at Dzongri in Sikkim, at 4200 to 4300 m in August, an elevation and late-summer flowering season fully characteristic of the species, where it grows in herb-rich turf above the treeline among the rolling alpine pastures of the upper Rathong valley.

The plant is a low, erect to ascending perennial herb arising from a tuberous, paired rootstock. The leaves are deeply palmately divided into narrow, again-lobed segments, dark green and mostly basal or on the lower stem. The inflorescence is a few-flowered terminal raceme of large, showy, deep blue to violet flowers. As in all Aconitum the flowers are strongly zygomorphic: the uppermost of the five petaloid sepals is enlarged into a tall, helmet-shaped hood (the galea) arching over two long-clawed nectariferous petals concealed within, the remaining sepals spreading. The numerous stamens surround several free carpels that mature into a cluster of follicles releasing winged or angled seeds.

Aconitum (monkshood; subfamily Ranunculoideae of the Ranunculaceae) is a large genus of the northern temperate and alpine zones, richly represented in the Sino-Himalaya. The hooded flowers are specialised for pollination by long-tongued bumblebees, which alone can reach the nectaries within the galea. Like its congeners A. hookeri contains highly toxic diterpenoid alkaloids of the aconitine type, rendering the whole plant dangerously poisonous yet of interest in traditional medicine. Restricted to high alpine grassland, it is locally frequent and not presently of conservation concern.

Author: Stapf · Sources: POWO (Kew), GBIF, Flora of Bhutan, Flora of China, Aconitum monograph (Tamura/Rapaics, Ranunculaceae)

Ranunculaceae

Aconitum lethale

by GP Jürgens

Griff.

Sikkim2003 440 P612
Sikkim Chopta Valley 3900m August
Sikkim2003 441 P613
Sikkim Chopta Valley 3900m August
Bhutan2012 39
Bhutan Shele-La, 3600m September
Bhutan2015 21
Bhutan2015 22
Bhutan Dochu-La 3000m, October
Bhutan2012 176
Bhutan Haar-Valley 3500m, September

Description

Aconitum lethale is an eastern Himalayan monkshood restricted to Nepal, India and Bhutan, with about 176 GBIF records concentrated in Sikkim and Bhutan. It is a plant of the upper subalpine and alpine zone, growing among tall-herb meadows, rhododendron and juniper scrub, and along moist, open slopes. The cited collections trace its habitat closely: the Chopta Valley in Sikkim at around 3900 m in August, and several Bhutanese sites including Shele-La at about 3600 m, the Haar Valley at 3500 m and Dochu-La near 3000 m, flowering from late summer into October. It favours cool, humid, well-drained mountain soils where the monsoon sustains lush herbaceous growth.

The plant is an erect perennial herb arising from tuberous roots, with a leafy stem bearing palmately divided, deeply lobed leaves whose segments are further incised. The inflorescence is a terminal raceme or panicle of the characteristic zygomorphic flowers, in which the upper sepal is enlarged into a tall, helmet-shaped or hooded galea concealing two long-clawed nectaries; the flowers are typically deep blue to violet. Numerous stamens surround several free carpels, which ripen into a cluster of dehiscent follicles releasing winged or angular seeds.

Described by Griffith, A. lethale is, as both its epithet and generic affinity warn, intensely poisonous, containing diterpenoid alkaloids of the aconitine type throughout the plant and especially in its tubers. Such alkaloids underlie the cautious medicinal use of Himalayan aconites in traditional pharmacopoeias. As a narrow-range endemic of the eastern Himalaya, it warrants attention to grazing pressure and habitat change, though it remains locally frequent within its restricted distribution.

Author: Griff. · Sources: POWO (Kew), GBIF, Flora of Bhutan, Annotated Checklist of the Flowering Plants of Nepal, Tamura's treatment of Aconitum

Ranunculaceae

Aconitum naviculare

by GP Jürgens

Stapf

Sikkim2003 256 P351
Sikkim Dzongri 4200m August

Description

Aconitum naviculare is a high-alpine monkshood of the eastern and central Himalaya, ranging from Nepal through Sikkim and northern India into Bhutan, south-western China (Xizang) and northern Myanmar; its modest tally of around 110 georeferenced occurrences (CN, NP, BT, IN, MM) reflects its specialised montane niche. It occupies open alpine meadows, screes, moist turf and rocky slopes at high elevation, typically between about 3500 and 4800 m. The plant photographed at Dzongri in Sikkim at 4200 m in August, flowering at the height of the monsoon-influenced alpine summer, exemplifies its cold, exposed habitat near the upper limit of vascular plant growth.

It is a small perennial herb arising from a slender tuberous rootstock, with an erect or somewhat flexuous stem usually under 30 cm. The leaves are palmately divided into narrow, deeply cut segments. The flowers are few and borne in a lax terminal raceme; as in all Aconitum the five petaloid sepals are zygomorphic, the uppermost forming the characteristic helmet or hood (galea), here narrowly boat-shaped (navicular, whence the epithet), bluish-purple and often paler within. Two long-clawed nectariferous petals are concealed beneath the hood, with numerous stamens and three to five free carpels ripening into a cluster of follicles containing winged seeds.

Aconitum naviculare belongs to subgenus Aconitum and is a noted constituent of Himalayan alpine flora, valued and harvested in Tibetan and folk medicine as "Bonga" for its diterpenoid alkaloids, which render the whole plant highly toxic. Such harvesting, combined with its restricted high-altitude range, raises local conservation concern, although it remains frequent within intact alpine grassland.

Author: Stapf · Sources: POWO (Kew), GBIF, Flora of China, Flora of Bhutan, Flora of Nepal, Stapf's monograph of the Asiatic species of Aconitum

Polygonaceae

Aconogonum campanulatum 

by GP Jürgens

(Hook.f.) H.Hara

Sikkim2003 70 P95
Sikkim Choka 2900m, August

Description

Aconogonum campanulatum, treated by GBIF as a synonym of the accepted Aconogonon campanulatum, is a Sino-Himalayan perennial herb distributed from Nepal and northern India through Sikkim and Bhutan into Myanmar and south-western China. Its 372 GBIF records lie mostly within this native range, with scattered European, North and South American and New Zealand points reflecting cultivated and herbarium material. It grows in subalpine and alpine meadows, forest clearings, shrubberies and along streamsides and banks, commonly between about 2700 and 4000 m. The plant photographed at Choka in Sikkim at 2900 m in August captures it flowering in moist, herb-rich montane vegetation during the monsoon.

It is a robust, branching perennial arising from a woody rootstock, with erect leafy stems. The leaves are alternate, ovate to ovate-lanceolate, often somewhat cordate to rounded at the base and acuminate at the apex, frequently white-tomentose beneath, with membranous sheathing ochreae at the nodes. The flowers are borne in lax, branched, paniculate inflorescences; each has a five-parted, campanulate, white to pinkish perianth (the source of the epithet), with eight stamens and a trifid style. The fruit is a small, trigonous, shining brown nut.

The species belongs to Aconogonon (often spelled Aconogonum), a segregate of the broadly defined Polygonum embracing the alpine knotweeds, and the accepted name is Aconogonon campanulatum. Its woody rootstock and tall leafy habit suit the tall-herb communities of moist Himalayan slopes. Widely distributed and locally abundant, it is of no conservation concern and forms a conspicuous element of subalpine meadow vegetation.

Author: (Hook.f.) H.Hara · Sources: POWO (Kew), GBIF, Flora of Bhutan, Flora of China, Annotated Checklist of the Flowering Plants of Nepal

Ranunculaceae

Actaea elata

by GP Jürgens

Prantl

Sikkim2003 477 P662
Sikkim Lachung Valley 3300m, August

Description

Actaea elata Prantl is a tall woodland perennial of cool-temperate forests. The GBIF record (CN, IN and several extralimital codes including US, CA, RU, CO and ZZ, totalling 844 occurrences) reflects a mixture of Asian native material and considerable confusion with the North American A. elata (Nutt.) Prantl, a name applied on both continents; in the Himalayan context the plant occupies shaded, humus-rich Abies–Betula and mixed broad-leaved forest, streamsides and tall-herb communities. The illustrated specimen from the Lachung Valley in northern Sikkim at 3300 m, in August, sits squarely within this moist montane forest zone, flowering and fruiting during the late monsoon.

The species grows from a stout rhizome, producing erect stems to well over a metre. The leaves are large, alternate and 2–3-ternately compound, the ultimate leaflets ovate, acuminate and sharply serrate to incised. Flowers are borne in elongate terminal and axillary racemes; they are small, white and apetalous in effect, the petaloid sepals soon caducous and the conspicuous part being the numerous slender white stamens, giving a fluffy aspect typical of baneberries. The pistils mature into several-seeded follicles or, in the strict baneberry sense, fleshy berries, the dispersal unit varying with the taxonomic circumscription applied.

Actaea, here treated to include the segregate Cimicifuga, belongs to subfamily Ranunculoideae; the inclusion of Cimicifuga within Actaea is supported by molecular phylogenetics. As in many Ranunculaceae the plants contain bioactive triterpene glycosides, conferring toxicity and underpinning medicinal use. The taxon is widespread and not threatened, though the transcontinental nomenclatural overlap means GBIF distributional data require critical evaluation.

Author: Prantl · Sources: POWO (Kew), GBIF, Flora of China (Ranunculaceae), Flora of Bhutan, Compton & Culham monograph of Actaea s.l. (incl. Cimicifuga)

Actinidiaceae

Actinidia callosa

by GP Jürgens

Lindl.

Bh09 44 P81
Bhutan Paro 2500m, June

Description

Actinidia callosa Lindl. is a woody climber of the Actinidiaceae, the kiwifruit family, distributed widely through the Himalaya and East and Southeast Asia. GBIF (about 3,400 occurrences) records it from China, Taiwan, Nepal, India, Japan, Vietnam, Myanmar, Bhutan and Indonesia, where it scrambles through montane broad-leaved and mixed forest, along forest margins, thickets and stream banks. It occupies a broad temperate to warm-temperate belt; the plant photographed at Paro in Bhutan at 2,500 m in June illustrates its flowering in mid-elevation forest, where it climbs over shrubs and trees for support.

The plant is a deciduous, twining liana with terete, lenticellate stems and a pith that is typically lamellate (chambered) or solid, a diagnostic character within the genus. Leaves are alternate, long-petiolate, ovate to elliptic, with finely serrate margins bearing callose-tipped teeth, the feature giving the epithet "callosa"; the lower surface is often glabrous to sparsely hairy with conspicuous venation. The flowers are borne in axillary cymes, are usually functionally unisexual (the plants more or less dioecious), and have white to greenish-white petals; the numerous stamens bear dark anthers, and the superior ovary develops many styles. The fruit is a many-seeded berry, ovoid to oblong, greenish to brownish and spotted, edible though far smaller than the cultivated kiwifruit.

Actinidia callosa is a polymorphic species with several recognised varieties differing in leaf indumentum, dentition and fruit characters, and it belongs to the same genus as the commercial kiwifruit (A. deliciosa and A. chinensis), making the wild Himalayan members of interest as genetic resources. Ecologically it is a characteristic forest liana, its berries dispersed by birds and mammals, and it contributes to the structural complexity of mid-montane Asian forests.

Author: Lindl. · Sources: POWO (Kew), Flora of China Vol. 12, Flora of Bhutan Vol. 1, GBIF, Li, Li & Soejarto: Actinidiaceae in Flora of China

Sapindaceae

Aesculus indica

by GP Jürgens

(Wall. ex Cambess.) Hook.

Nepal 97 610 G1181
Nepal Godawari 1350m May
Garh 07 82 ergebnis
India Garhwal Trijugi Narayan 2300m, June

Description

Aesculus indica ((Wall. ex Cambess.) Hook.), the Indian horse-chestnut, is a large deciduous tree endemic to the western and central Himalaya, occurring from Afghanistan and Pakistan through northern India and Nepal to Bhutan. The roughly 1,140 GBIF records, supplemented by numerous cultivated occurrences in Britain, Europe and North America, reflect both its native montane range and its popularity as an ornamental and avenue tree. It is a characteristic component of moist temperate forest, growing along streamsides, in shady ravines and on cool north-facing slopes, generally between 1,200 and 3,000 m, as illustrated by the Nepal record from Godawari at 1,350 m in May and the Garhwal collection from Trijugi Narayan at 2,300 m in June.

The tree reaches 20–30 m, with a broad rounded crown and smooth greenish-grey bark. The leaves are opposite and palmately compound, with five to nine lanceolate, finely serrate, long-acuminate leaflets that are sessile to shortly stalked and taper to the base. The flowers are borne in large, erect, terminal thyrses (panicles) up to 30 cm long; each flower is white to pinkish with a yellow or red blotch at the base of the petals, the stamens long-exserted. The fruit is a large, rough, pyriform, spineless capsule containing one to three glossy dark-brown seeds ("conkers").

The seeds are rich in bitter saponins and, after laborious leaching to remove toxicity, have traditionally been ground into a flour ("tattwakhar" or "bankhor") used as famine food and livestock fodder in the Himalaya. Distinguished from the European A. hippocastanum by its smooth, unarmed fruit and narrower leaflets, A. indica is widely planted for shade and timber. Though locally heavily exploited, the species remains relatively common within its range.

Author: (Wall. ex Cambess.) Hook. · Sources: POWO (Kew), Flora of Pakistan, GBIF, Flora of China Vol. 12, Hardin: A Revision of the American Hippocastanaceae and the genus Aesculus

Asteraceae

Ageratum houstonianum

by GP Jürgens

Mill.

Sikkim2011 9
India Sikkim Tista valley 1800m, June

Description

Ageratum houstonianum Mill. is native to Mexico and Central America but is now a widely naturalised tropical and subtropical weed; GBIF records over 25,000 occurrences spanning Mexico, the United States, China, Taiwan, Hong Kong, Nepal, India, South Africa, Tanzania, Malawi and much of western and central Europe. It colonises waste ground, roadsides, field margins, ditches and clearings, particularly in moist, disturbed habitats. The record from the Tista valley in Sikkim at 1800 m in June reflects its thorough naturalisation in the lower Eastern Himalaya, where it flowers through the warm, humid monsoon season.

It is an erect to ascending annual herb with stems clothed in spreading, often viscid hairs. The leaves are mostly opposite, ovate to deltoid, with a crenate-serrate margin, a truncate to cordate base and conspicuous palmate venation, and are softly pubescent. The small capitula are aggregated in dense, flat-topped corymbs; each head is wholly discoid, lacking ray florets, with an involucre of narrow phyllaries and numerous blue, lavender or occasionally white tubular florets whose long, exserted styles give the inflorescence a characteristic fluffy texture. The fruit is a black, five-angled cypsela bearing a pappus of awned scales.

Widely grown as the ornamental "floss flower", A. houstonianum has escaped cultivation throughout the warmer world and is regarded as an invasive weed in parts of Asia, Africa and Australia; like its relatives it contains pyrrolizidine alkaloids and is toxic to livestock. It is of no conservation concern and is instead managed as a weed.

Author: Mill. · Sources: POWO (Kew), GBIF, Flora of China, Flora of North America, Johnson revision of Ageratum

Lamiaceae

Ajuga lupulina

by G & P Jürgens

Maxim.

Nepal 99 387 ergebnis
West-Nepal Sallibagar-Khola 3100m, June

Description

Ajuga lupulina is a robust perennial herb of the Sino-Himalayan region, distributed across China, Nepal and India and extending into Mongolia; GBIF logs about 1205 occurrences with its centre in the Tibetan Plateau borderlands and the high Himalaya. It grows on open alpine and subalpine slopes, gravelly pastures, riverbanks and stony meadows, generally between about 2500 and 4300 m. The photographed plant was found in West Nepal at Sallibagar Khola at roughly 3100 m in June, a typical setting for this conspicuous species among the early-summer flora of the western Himalayan valleys.

The species is an erect perennial arising from a stout rootstock, with quadrangular stems that are villous, especially at the nodes. The leaves are opposite, oblong-lanceolate to elliptic, toothed and softly hairy. The plant is most readily recognised by its dense, elongate, spike-like terminal inflorescence in which large, broadly ovate, often pale or purplish-tinged floral bracts overlap conspicuously and conceal the flowers, giving a hop-like aspect that explains the epithet lupulina. The flowers have a bilabiate corolla with a much-reduced upper lip and a conspicuous trilobed pale yellowish to whitish lower lip; the four stamens are didynamous and exserted. The fruit comprises four reticulate nutlets enclosed by the persistent calyx.

Ajuga lupulina Maxim. is widespread and common across its broad Sino-Himalayan range and of no conservation concern. It is valued in traditional Tibetan and Chinese herbal medicine, and the genus is known for neo-clerodane diterpenoids and ecdysteroids. Its large imbricate bracts make it one of the most recognisable Himalayan bugles and a useful field marker of alpine pastures.

Author: Maxim. · Sources: POWO (Kew), GBIF, Flora of China, Flora of Nepal, taxonomic revisions of Ajuga (Lamiaceae)