Author

GP Jürgens

Potamogetonaceae

Potamogeton distinctus

by GP Jürgens

A.Benn.

Bhutan2015 560
Bhutan Mo-Chu 1500m, October

Description

Potamogeton distinctus is an aquatic herb widespread across temperate and subtropical Asia, recorded from Japan, Korea, China, Taiwan and the Russian Far East through the Himalaya (India, Nepal, Bhutan) into Southeast Asia and beyond. It is a plant of still and slow-moving fresh water — ponds, ditches, paddy fields, oxbows and the margins of slow rivers — from the lowlands to the lower montane belt. The individual photographed along the Mo Chu in Bhutan at 1,500 m in October illustrates its occurrence in a sluggish river backwater of the inner valleys, where it persists into autumn. It is well known as a weed of rice cultivation across its eastern range.

It is a perennial rooting in mud and spreading by slender, whitish, often tuber-bearing rhizomes. The plant is heterophyllous: submerged leaves are translucent, narrow and sessile or short-petioled, while the floating leaves are coriaceous, elliptic to oblong, long-petioled and with rounded to subcordate bases. Membranous stipules (ochreae) sheath the stem at the nodes. The inflorescence is a dense, cylindrical, emergent spike raised above the water on a stout peduncle; the small flowers each bear four clawed tepal-like segments and four stamens. The fruit is a small, obliquely obovoid drupelet with a short beak and a dorsal keel.

Potamogeton (Potamogetonaceae) is a cosmopolitan genus prone to hybridisation and to plastic, environmentally induced variation, which complicates identification; floating-leaved species such as P. distinctus are best separated on fruit, stipule and tuber characters. The species is widespread, often abundant, and of no conservation concern, though as a paddy weed it is locally controlled.

Author: A.Benn. · Sources: POWO (Kew), Flora of China Vol. 23, Flora of Bhutan Vol. 3, GBIF, Wiegleb & Kaplan: Account of Potamogeton (1998)

Potamogetonaceae

Potamogeton nodosus

by GP Jürgens

Poir.

Sikkim2003 516 G716
Sikkim Yume Samdong 4700m August

Description

Potamogeton nodosus Poir. is a cosmopolitan aquatic perennial of the Potamogetonaceae, one of the most widely distributed pondweeds. Its extensive GBIF record (over 40,000 occurrences) spans Europe, the Americas, North Africa, the Middle East, and temperate Asia including China and Japan, reflecting a near-global range in suitable freshwater habitats. It was recorded in Sikkim at Yume Samdong at the remarkable altitude of 4,700 m in August, an unusually high station that illustrates the species' tolerance of cold, high-altitude standing and slow-flowing waters. It typically colonises ponds, ditches, lakes, and gently flowing rivers on fine, nutrient-rich substrates.

The plant is rooted, with a creeping rhizome bearing slender, branching stems. It is heterophyllous: the floating leaves are long-petiolate, elliptic to oblong, leathery and parallel-veined, while submerged leaves, when present, are narrower and more translucent. The membranous stipules are conspicuous and free from the leaf base. Small greenish flowers are borne in a dense, emergent, cylindrical spike on a stout peduncle; pollination is by wind and water, and the fruit is a small, beaked, dorsally keeled drupelet.

Potamogeton nodosus belongs to a taxonomically difficult genus prone to hybridisation, with broad-leaved species often requiring careful examination of fruit and stipule characters for identification. As a near-cosmopolitan generalist it is of no conservation concern; indeed it can become locally dominant in nutrient-enriched waters. Its presence provides oxygenation, food, and shelter within freshwater ecosystems.

Author: Poir. · Sources: POWO (Kew), Flora of China Vol. 23, Flora of Pakistan, GBIF, Wiegleb & Kaplan: Account of the Species of Potamogeton (1998)

Rosaceae

Potentilla coriandrifolia

by GP Jürgens

D.Don

Sikkim2003 132 G180
Sikkim Dzongri 3900m, August
Sikkim2003 133 W181
Sikkim Dzongri 3900m, August

Description

Potentilla coriandrifolia D.Don is a high-alpine perennial distributed across the eastern and central Himalaya and adjacent mountains, recorded from China, Nepal, India, Bhutan and Myanmar, with extralimital cultivated records elsewhere; some 542 georeferenced occurrences are documented in GBIF. It inhabits open turf, stony alpine meadows, gravelly slopes and the margins of moraines, typically between 3500 and 4800 m. The photographed plant grows at Dzongri in Sikkim at about 3900 m, flowering in August, a setting typical of the cool, well-drained alpine sward where this cushion-forming herb thrives among dwarf rhododendrons and graminoids.

The plant develops from a stout, woody, branched rootstock crowned by the persistent remains of old petioles, forming low tufts or loose mats. The leaves are radical, pinnate or pinnatisect with a coriander-like (coriandrifolium) dissection, the leaflets deeply incised into narrow oblong segments and often somewhat glaucous or silky beneath. Flowering stems are slender, ascending and few-flowered. The flowers are typically yellow, occasionally suffused with reddish or purplish tones at the base of the petals, with five obcordate petals exceeding the calyx, an epicalyx alternating with the sepals, and numerous stamens surrounding a central tuft of carpels. The fruit is an aggregate of dry achenes seated on a hairy receptacle.

A member of the large and taxonomically intricate genus Potentilla, this species belongs to the assemblage of dwarf Himalayan cinquefoils adapted to short growing seasons and intense insolation. Its distinctive finely cut foliage distinguishes it from related alpine taxa such as P. microphylla. Though not assessed as threatened, populations are restricted to fragile high-altitude habitats sensitive to grazing pressure and climate-driven upslope shifts, making the species a useful indicator of alpine ecosystem condition.

Author: D.Don · Sources: POWO (Kew), GBIF, Flora of China, Flora of Bhutan, Annotated Checklist of the Flowering Plants of Nepal, Soják monograph of Potentilla

Rosaceae

Potentilla fruticosa var. arbuscula

by GP Jürgens

(D.Don) Maxim.

Sikkim2003 189 P260
Sikkim Dzongri 4100m, August

Description

Potentilla fruticosa var. arbuscula is a shrubby cinquefoil of the high mountains of the Sino-Himalayan region, recorded from China, Nepal, Bhutan and Japan. GBIF treats the name as a synonym, with Potentilla fruticosa var. arbuscula (here cited following the source) regarded as the accepted designation for this entity; in modern treatments the shrubby cinquefoils are often placed in the segregate genus Dasiphora. It grows in alpine and subalpine scrub, open meadows, rocky slopes and stream-sides above and near the treeline, generally between about 3000 and 4500 m. The photographed plant comes from Dzongri in Sikkim at around 4100 m, flowering in August. With over 400 georeferenced records it is a well-documented high-montane shrub.

It forms a low, much-branched deciduous shrub, often spreading or cushion-like at the highest elevations, the bark shredding and the young shoots silky-hairy. The leaves are pinnate with usually five small, narrow, oblong leaflets that are green above and densely silvery-silky beneath, with revolute margins. The flowers are solitary or few in the leaf axils and at the branch tips; each has five green sepals alternating with epicalyx segments and five broad, rounded, golden-yellow petals exceeding the calyx. The numerous stamens surround a hairy receptacle bearing many free carpels, which ripen into a head of small hairy achenes.

The shrubby cinquefoil complex is taxonomically intricate and widely cultivated in horticulture; var. arbuscula is distinguished within it by its dense indumentum and Himalayan high-altitude form. Its abundant nectar-rich flowers attract a range of insect pollinators. As a common and broadly distributed alpine shrub it is of least conservation concern.

Author: (D.Don) Maxim. · Sources: POWO (Kew), GBIF, Flora of China, Flora of Bhutan, Soják's revisions of Potentilla and Dasiphora

Rosaceae

Potentilla fruticosa var. pumila

by GP Jürgens

Hook.f.

BhutanPG2011 530
Bhutan Ludlow-Sherriff-Trail Dem-Tso, 4000m June
Sikkim2003 290 P401
Sikkim Saniti-Lake, 4300m August

Description

This dwarf shrubby cinquefoil belongs to the widespread circumboreal complex now placed by many authorities in the genus Dasiphora, the name GBIF treats as accepted; the very large occurrence total of over 83,000 reflects the broad species aggregate across North America, Europe and northern Asia, including China. The taxon is a true alpine, growing on stony pastures, lake shores, moraines and exposed rocky slopes near and above the treeline. The recorded high-Himalayan plants from Dem-Tso on the Ludlow-Sherriff Trail in Bhutan at 4000 m in June and from Saniti Lake in Sikkim at 4300 m in August represent prostrate dwarf forms of the cold, windswept upper alpine zone.

It is a low, much-branched deciduous shrub, in this variety dwarf and often mat-forming, with shredding brown bark on the older stems. The leaves are pinnate with usually five small, oblong to elliptic, entire leaflets that are silky-hairy and somewhat revolute at the margins, with conspicuous stipules. The flowers are solitary or few, with five rounded yellow petals, numerous stamens, and an epicalyx alternating with the green calyx lobes. The fruit is a head of small, hairy achenes typical of the genus.

The dwarf variety pumila is one of several poorly delimited high-elevation forms within a polymorphic, taxonomically contested group spanning Potentilla, Dasiphora and Pentaphylloides. Hardy and stress-tolerant, the shrub is a pioneer of skeletal alpine soils and a familiar component of treeline scrub across the Northern Hemisphere, of biogeographic interest as a connecting element between Himalayan and arctic floras.

Author: Hook.f. · Sources: POWO (Kew), GBIF, Flora of China, Flora of Bhutan, Soják's revisions of Dasiphora and Potentilla

Rosaceae

Potentilla lineata

by GP Jürgens

Trevir.

Bh09 289 P475
Bhutan Tongsa, 2300m June
Garw 2005 284 ergebnis
India Garhwal Kunol 2650m, September

Description

Potentilla lineata is a widespread Asian cinquefoil ranging across the Himalaya and into China, Myanmar and Vietnam, well represented in GBIF with around 519 records from China, Nepal, India, Bhutan, Pakistan and beyond. In GBIF the queried name is treated as a synonym, with Potentilla lineata itself given as the accepted name. It occupies open grassy slopes, forest clearings, banks, pastures and disturbed roadsides through the temperate and subalpine belts, roughly 1500 to 3500 m. The collections cited from Tongsa in Bhutan at 2300 m in June and from Kunol in the Garhwal Himalaya at 2650 m in September show its long flowering season across the monsoon.

It is a perennial herb with a woody rootstock producing erect to ascending, often silky-hairy stems. The leaves are pinnate or digitately compound with toothed, oblong to obovate leaflets that are typically green and appressed-hairy above and densely silvery- or white-tomentose beneath, the strongly impressed venation giving rise to the epithet lineata. The flowers are borne in lax terminal cymes; each has five yellow petals alternating with an epicalyx and five sepals, numerous stamens and many carpels seated on a hairy receptacle. The fruit is an aggregate of small dry achenes.

Potentilla is a large and taxonomically complex genus in which hybridisation and polyploidy blur species boundaries, and P. lineata has accordingly accumulated several synonyms. The silvery indumentum reduces water loss and reflects intense montane radiation. With its broad ecological tolerance and ready colonisation of disturbed ground, the species is common and of no conservation concern, functioning as a characteristic component of Himalayan grazing land and successional grassland.

Author: Trevir. · Sources: POWO (Kew), GBIF, Flora of China (Rosaceae), Flora of Bhutan, Annotated Checklist of the Flowering Plants of Nepal, Soják taxonomic studies of Potentilla

Rosaceae

Potentilla microphylla

by GP Jürgens

D.Don

Bh09 163 G288 1
Bhutan Labana, 4100m June
Garh 07 374 ergebnis
Garh 07 375 ergebnis
India Garhwal Khiar Kutti 3900m, June
Sikkim2003 505 G705 ergebnis
Sikkim Yume Samdong 4400m, August

Description

Potentilla microphylla D.Don is a dwarf, cushion-forming cinquefoil of the high Himalaya and Tibetan borderlands, occurring through China, India, Nepal and Bhutan. Reliable verbatim occurrence and country totals in the source record are unfortunately conflated with family-level aggregate figures, so the very large occurrence count and the European-dominated country list cited there pertain to the family Rosaceae rather than to this species, which is genuinely a high-alpine Himalayan endemic. It grows on exposed rocky ridges, screes, gravelly flats and crevices, typically between about 3500 and 5000 m. The illustrated plants come from Labana in Bhutan (4100 m, June), Khiar Kutti in Garhwal, India (3900 m, June), and Yume Samdong in Sikkim (4400 m, August), all severe high-alpine stations.

The plant forms dense, low cushions or mats from a woody, much-branched rootstock clothed in persistent old leaf bases. The leaves are crowded, small and pinnate with several pairs of tiny, closely set leaflets (the epithet microphylla, small-leaved), the leaflets often coriaceous, revolute-margined and silky or glabrescent. The flowers are usually solitary on short stalks barely exceeding the foliage, with five yellow, broadly obcordate petals longer than the sepals, an epicalyx, numerous stamens and a central cluster of carpels. The fruit is an aggregate of small dry achenes seated on a hairy receptacle.

Within Potentilla this species belongs to the dwarf, densely caespitose alpine cinquefoils, its compact cushion habit conserving warmth and moisture against wind and intense radiation. It is readily distinguished from the finely dissected P. coriandrifolia by its small, regularly pinnate, leathery leaflets. The species is widespread across its high-elevation belt and not of conservation concern, but is a characteristic component of fragile alpine cushion communities.

Author: D.Don · Sources: POWO (Kew), GBIF, Flora of China, Flora of Bhutan, Annotated Checklist of the Flowering Plants of Nepal, Soják monograph of Potentilla

Rosaceae

Potentilla peduncularis

by GP Jürgens

D. Don

Sikkim2011 228
Sikkim Yumthang 3700m, June
BhutanPG2011 224
Bhutan Tsochenchen, 3600m June

Description

Potentilla peduncularis is a Sino-Himalayan cinquefoil recorded in GBIF from China, Nepal, India, Bhutan, Pakistan and Myanmar across 239 occurrences. It occupies alpine and subalpine meadows, grassy slopes, open scrub and stream margins, typically between 3000 and 4300 m. The photographed plants were recorded at Yumthang in Sikkim at about 3700 m and at Tsochenchen in Bhutan at 3600 m, both in June, when long days and snow-melt moisture drive the early summer flush of flowering on these high pastures.

It is a tufted perennial herb arising from a stout, woody, branched rootstock, producing ascending to spreading flowering stems 15-40 cm tall that are clothed in spreading hairs. The leaves are pinnate (imparipinnate) with several pairs of oblong, deeply serrate to incised leaflets that are green and pilose above and densely white- to grey-tomentose beneath, giving a bicoloured aspect. The inflorescence is a lax, long-pedunculate cyme of yellow flowers, each with five sepals alternating with epicalyx segments, five obcordate petals, and numerous stamens surrounding a domed receptacle of carpels. The fruit is an aggregate of small, glabrous achenes.

Although widely accepted, the name is treated in GBIF as a synonym, with Potentilla peduncularis itself given as the accepted name; the species sits within the large, taxonomically intricate genus Potentilla (Rosaceae, subfamily Rosoideae), where the dense white leaf indumentum is a useful diagnostic among Himalayan yellow-flowered cinquefoils. Pollination is by generalist insects, and the dry achenes are dispersed passively. It is locally frequent and not regarded as threatened.

Author: D. Don · Sources: POWO (Kew), GBIF, Flora of China, Flora of Bhutan, Flora of Pakistan, Soják revision of Asian Potentilla

Rosaceae

Potentilla polyphylla

by GP Jürgens

Schur

BhutanPG2011 396
Bhutan Tsochenchen, 3550m June
D444371527264B45943B2C738598F852 1
Bhutan Dur-Tso-Chu, 3500m June

Description

Potentilla polyphylla is a Himalayan and Sino-Himalayan cinquefoil ranging through Nepal, north-east India, Bhutan, south-west China, Myanmar, Afghanistan and Pakistan, with 340 georeferenced occurrences. It is a plant of open alpine and subalpine habitats, occupying grassy slopes, meadows, rocky banks, stream margins and the moist turf around glacial lakes. The Bhutan collections at Tsochenchen (3550 m) and Dur-Tso-Chu (3500 m), both in June, place it firmly in the high-alpine zone, typically between about 3000 and 4300 m. GBIF treats the supplied name as a synonym while retaining Potentilla polyphylla as the accepted name; it has at times been confused with Potentilla leuconota.

It is a perennial herb arising from a stout, woody rootstock, producing tufted basal leaves and ascending flowering stems. The leaves are pinnately compound (interrupted-pinnate) with numerous small, closely set, oblong-obovate leaflets that are sharply toothed and silky-hairy, especially beneath. The flowers are borne in lax terminal cymes; each has five green sepals alternating with an epicalyx, five rounded yellow petals, numerous stamens, and many free carpels seated on a hairy receptacle. The fruit is a cluster of small dry achenes.

Within the large genus Potentilla the species sits among the pinnate-leaved high-mountain cinquefoils, a taxonomically intricate group where leaf division and indumentum provide key diagnostic characters. The open yellow flowers are pollinated by a variety of alpine insects. Widely distributed across the Himalayan arc and tolerant of grazed pasture, it is not regarded as threatened, and like other alpine Potentilla species it has local ethnobotanical uses.

Author: Schur · Sources: POWO (Kew), GBIF, Flora of Bhutan, Flora of China, Flora of Nepal, Soják Potentilla taxonomic revisions

Rosaceae

Potentilla reptans

by GP Jürgens

L.

Sikkim2003 475 G660
Sikkim Lachung Valley 3200m August

Description

Potentilla reptans, creeping cinquefoil, is an exceptionally widespread Eurasian and North African perennial, one of the commonest of all temperate herbs, with over 740,000 GBIF occurrences dominated by European records from France, Britain, the Netherlands, Germany, Scandinavia, Iberia and Russia, alongside its introduced range. It thrives in grassland, roadsides, meadows, lawns and disturbed moist ground from lowlands to montane elevations. In the Himalaya it occurs as a native or naturalised element, as documented in the Lachung Valley of Sikkim at 3200 m in August, where it grows along damp valley tracks and pasture edges during the monsoon.

It is a prostrate, stoloniferous perennial spreading by long slender runners that root at the nodes to form extensive mats. The leaves are long-petioled and palmately compound, usually with five obovate, coarsely toothed leaflets (hence "cinquefoil"), green and sparsely hairy. The flowers are solitary on slender axillary pedicels arising from the nodes, the corolla bright yellow with five broadly obcordate petals exceeding the epicalyx and calyx, surrounding numerous stamens and a dome of free carpels on a hairy receptacle. The fruit is an aggregate of small, dry, finely rugose achenes.

Potentilla is a large rosaceous genus and P. reptans is a model of clonal growth, reproducing efficiently by rooting stolons as well as by seed. Its open yellow flowers are visited by a broad range of generalist insects. As an aggressive colonist of disturbed ground it is of weedy rather than conservation significance and is among the most ecologically successful species in the genus.

Author: L. · Sources: POWO (Kew), GBIF, Flora Europaea, Flora of China, Flora of British India, Wolf monograph of Potentilla