Author

G & P Jürgens

Ericaceae

Lyonia villosa

by G & P Jürgens

(Wall. ex C.B. Clarke) Hand.-Mazz.

Lyonia villosa ergebnis scaled
Bhutan Wangdi, 2400m June

Description

Lyonia villosa (Wall. ex C.B.Clarke) Hand.-Mazz. is a widely distributed Sino-Himalayan shrub recorded from China, Nepal, Bhutan, India, Myanmar, Vietnam and Japan, with more than 1300 georeferenced occurrences in GBIF, reflecting its broad range across the eastern Himalaya and southern China. It grows in temperate forest, forest margins, thickets and open rocky hillsides, commonly between about 1500 and 3500 m. The plant photographed near Wangdi at 2400 m in June is characteristic of its mid-elevation habitat, where it forms part of the understorey and scrub of mixed broadleaved and conifer woodland.

It is a deciduous shrub or small tree with villous to tomentose young branchlets, the indumentum giving rise to the epithet. The leaves are alternate, ovate to elliptic, entire, with a pubescent surface and prominent venation. The white, urceolate (urn-shaped) flowers are borne in axillary racemes or fascicles along the branches; each corolla is shortly five-lobed at the contracted mouth, with included stamens whose anthers bear awns, and a superior ovary maturing into a woody, dehiscent, five-valved capsule. The capsule has thickened sutures, a diagnostic feature of the genus, and releases numerous small seeds.

Lyonia belongs to the tribe Lyonieae of the Ericaceae and is allied to Pieris and Agarista; the thickened capsule sutures and awned anthers separate it from these relatives. Several varieties have been recognised within L. villosa on the basis of indumentum density and leaf shape. As in many Ericaceae the foliage is reported to be toxic to livestock. The species is common and widespread and is not considered threatened.

Author: (Wall. ex C.B. Clarke) Hand.-Mazz. · Sources: POWO (Kew), GBIF, Flora of China, Flora of Bhutan, Judd revision of Lyonia (Ericaceae)

Primulaceae

Lysimachia congestiflora

by G & P Jürgens

Hemsl.

Bhutan2014 782
Bhutan Wangdi Mo-Chu 1200m, May

Description

Lysimachia congestiflora is a wide-ranging species native across China, Taiwan, the Himalaya (Nepal, north-east India, Bhutan) and into Myanmar, Vietnam, Laos, Thailand and Japan; its very large total of 1844 georeferenced records includes numerous naturalised and cultivated points in the United States, Brazil, Ecuador, Mexico, Australia and Europe, reflecting its popularity as a creeping ground-cover and basket plant. It grows in moist, shaded to open ground on grassy banks, streamsides, ditches, field margins and damp roadside slopes. The Bhutan collection at Wangdi along the Mo-Chu at about 1200 m typifies its preference for warm, humid lower-montane habitats.

It is a low, mat-forming perennial herb with slender, decumbent to creeping stems that root at the lower nodes and are sparsely villous. The leaves are opposite, ovate to broadly elliptic, often gland-dotted and minutely hairy. The flowers are crowded in dense terminal clusters (hence congestiflora), each on a short pedicel; the corolla is yellow, rotate to broadly campanulate, five-lobed and frequently marked with reddish spots or a darker throat. There are five stamens, and the fruit is a small globose capsule enclosed by the persistent calyx.

Within Primulaceae the genus Lysimachia (sometimes segregated as Lysimachiopsis or placed in subgenus Idiophyton) comprises loosestrifes characterised by rotate corollas and capsular fruit. The clustered yellow flowers attract a range of generalist insect pollinators. Exceptionally adaptable and frequently weedy in cultivation, the species is abundant throughout its native range and of no conservation concern; its capacity to naturalise has even made it a minor garden escape in several regions.

Author: Hemsl. · Sources: POWO (Kew), GBIF, Flora of China, Flora of Bhutan, Flora of Nepal, Hu & Kelso Primulaceae monographic treatments

Primulaceae

Lysimachia evalvis

by G & P Jürgens

Wall.

Sikkim 2006 282 ergebnis
Sikkim 2006 281 ergebnis
India West-Bengal, Chaana 1650m, May

Description

Lysimachia evalvis is a Sino-Himalayan herb distributed along the moist temperate and subtropical belt of the eastern Himalaya and adjacent Indo-Burmese ranges. GBIF records (88 occurrences) span India, Nepal, Myanmar, Bhutan, Bangladesh and China, with scattered cultivated or vouchered material noted from the United States. It favours shaded, humid forest margins, stream banks and seepage slopes within broadleaved woodland. The species was photographed at Chaana in West Bengal, India, at about 1650 m in May, in the lower montane forests where it flowers with the onset of the pre-monsoon rains.

It is a perennial, somewhat fleshy herb with slender erect to ascending stems arising from a short rhizomatous base. The leaves are alternate to subopposite, ovate to lanceolate, entire, acuminate at the apex and often gland-dotted, borne on short petioles. The flowers are solitary or few in the upper leaf axils, with a deeply five-lobed calyx and a yellow, rotate to campanulate corolla divided into five lobes; the five stamens are inserted on the corolla tube. The fruit is a small globose capsule; as the epithet evalvis suggests, dehiscence is reduced or irregular rather than by the typical valves, a diagnostic feature within the genus.

Lysimachia (Primulaceae, formerly segregated in Myrsinaceae alliance) is a large, near-cosmopolitan genus well represented in the Himalaya. L. evalvis belongs to the predominantly Asian element of the genus, its distribution reflecting the warm, perhumid forests of the eastern Himalayan front. No formal conservation assessment is widely published; like many forest-floor herbs of this region, its persistence depends on intact humid montane forest, making habitat conversion the principal threat to local populations.

Author: Wall. · Sources: POWO (Kew), GBIF, Flora of China, Flora of Bhutan, Annotated Checklist of the Flowering Plants of Nepal, Hu's monograph of Lysimachia (Primulaceae)

Didymocarpinae

Lysionotus pubescens

by G & P Jürgens

C.B. Clarke

Bhutan2012 996
Bhutan Thritangebe 1000m, October

Description

Lysionotus pubescens is an epiphytic or lithophytic gesneriad of the humid subtropical to lower montane forests of the eastern Himalaya and Indo-Burma, recorded from China, India, Bhutan, Myanmar, Vietnam and Sri Lanka. Its 75 georeferenced occurrences trace a belt of warm, moist evergreen forest where it grows perched on mossy tree trunks, branches and shaded rock faces. The plant photographed at Thritangebe in Bhutan at 1000 m in October reflects its preference for the warm, low-elevation forest zone, flowering in the post-monsoon period when humidity remains high beneath the canopy.

The plant is a small woody-based perennial with pendent or ascending stems bearing leaves in whorls of three or more, or sometimes opposite. The leaves are leathery, elliptic to oblong, with a toothed (serrate to crenate) margin, and as the epithet indicates the herbage is finely pubescent. The flowers are borne in short axillary cymes; the corolla is tubular and distinctly two-lipped (bilabiate), white to pale pink or pale violet, often with yellow or purple markings in the throat, with two fertile stamens. The diagnostic fruit is a long, slender, linear capsule that dehisces to release numerous minute seeds bearing fine appendages.

Lysionotus belongs to subtribe Didymocarpinae of the Gesneriaceae, the family group cited here, and is distinguished within it by its long siliqua-like capsule and frequently whorled leaves. The genus is centred on the Sino-Himalayan and Indo-Chinese region and is well represented in China. As an epiphyte dependent on intact humid forest, L. pubescens is locally common where suitable habitat persists but is sensitive to forest clearance.

Author: C.B. Clarke · Sources: POWO (Kew), GBIF, Flora of China, Flora of Bhutan, Gesneriaceae of the Old World monograph (Weber), Flowers of the Himalaya (Polunin & Stainton)

Euphorbiaceae

Macaranga denticulata

by G & P Jürgens

Müll.Arg.

Bhutan2015 199
Bhutan, Zhemgang 910m, October
Bhutan2015 557
Bhutan, Punaka 1240m, October
Bhutan2015 556
Bhutan, Punaka 1240m, October

Description

Macaranga denticulata is a fast-growing pioneer tree with a wide tropical and subtropical Asian distribution, its 1451 georeferenced occurrences spanning China, India, Nepal, Bhutan, Bangladesh, Myanmar, Thailand, Vietnam, Laos, Cambodia, Malaysia, Indonesia, the Philippines and beyond. It is a characteristic colonist of disturbed ground, forest gaps, road cuttings, secondary forest and abandoned swidden plots in warm, humid foothill country. The records from Zhemgang at 910 m and Punakha at 1240 m in Bhutan in October place it firmly in the low-elevation subtropical zone where it regenerates rapidly after disturbance and forms early-successional thickets and woodland.

The plant is a small to medium evergreen tree with smooth bark and somewhat whorled, spreading branches. The leaves are large, alternate, peltate or subpeltate, broadly ovate to triangular with a denticulate margin reflected in the epithet, palmately veined, and often bearing glands and pale tomentum beneath. As a member of the Euphorbiaceae it is dioecious, the small apetalous flowers borne in branched axillary inflorescences subtended by toothed or glandular bracts; male and female flowers occur on separate trees. The fruit is a small two-lobed capsule, the seeds often associated with a fleshy aril attractive to birds and ants.

Macaranga is a large palaeotropical genus famous for its myrmecophytic (ant-associated) species and its ecological role as a pioneer. M. denticulata is a non-myrmecophytic but ecologically important coloniser, valued for rapid biomass accumulation, soil stabilisation and as a nurse species in fallows. Its enormous range, abundance and affinity for disturbed habitats make it among the most secure and widespread trees in its family across tropical Asia.

Author: Müll.Arg. · Sources: POWO (Kew), GBIF, Flora of China, Flora of Bhutan, Revision of Macaranga (Euphorbiaceae) (Whitmore and successors), Trees of tropical Asia

Lauraceae

Machilus duthei

by G & P Jürgens

King ex Hook.f.

Sikkim 2006 409 ergebnis
Sikkim Ringi-Chu 3100m, May

Description

Machilus duthei is an evergreen laurel of the Himalaya, recorded from northern India, Nepal and Pakistan, with relatively few documented occurrences across this western to central Himalayan range. It is a tree of moist temperate broad-leaved evergreen forest, occurring on shaded slopes, in ravines and along forested watercourses. It grows at mid to upper montane elevations; the tree photographed near the Ringi-Chu in Sikkim at 3,100 m in May represents an upper-elevation occurrence in the cool, humid temperate forest belt, where laurels form a notable element of the canopy and subcanopy.

The plant is a medium-sized evergreen tree with smooth bark and glabrous to finely pubescent young shoots. The leaves are alternate, coriaceous, elliptic to oblong-lanceolate, entire, glabrous and glossy above, somewhat glaucous beneath, with pinnate venation and aromatic tissue typical of the family. The flowers are small, bisexual and trimerous, with six subequal perianth segments and stamens in whorls, the inner whorl glandular, borne in axillary or subterminal panicles. The fruit is a globose to ellipsoid berry seated on a persistent, slightly enlarged perianth cup at the apex of the pedicel.

The genus Machilus, closely allied to and sometimes merged with Persea, comprises evergreen Asian laurels of considerable importance in moist subtropical and temperate forest. Machilus duthei, described by King ex Hooker f. and commemorating the botanist J. F. Duthie, is a comparatively narrowly distributed Himalayan species. Given its limited documented range and dependence on undisturbed humid montane forest, it is vulnerable to habitat degradation and logging, and its sparse records indicate a need for further field survey to assess its true distribution and conservation status.

Author: King ex Hook.f. · Sources: POWO (Kew), Flora of China Vol. 7, Annotated Checklist of the Flowering Plants of Nepal, GBIF, Kostermans: Lauraceae studies

Lauraceae

Machilus kurzii

by G & P Jürgens

King ex Hook.f.

Sikkim2004 379 P656 ergebnis
Sikkim Lachung-valley 3200 m, May
Sikkim2004 380 P657 ergebnis
Sikkim Lachung-valley 3200 m, May

Description

Machilus kurzii is an evergreen laurel of the eastern Himalaya and Southeast Asia, distributed from NE India and Bhutan through Myanmar, Thailand, Cambodia and Vietnam into SW China, as documented by its roughly 135 GBIF occurrences across IN, BT, CN, MM, TH, KH, VN and KR. The tree photographed grows in the Lachung valley of northern Sikkim at about 3,200 m in May. It is a species of humid temperate and subtropical evergreen broadleaf forest, occurring on moist slopes and in ravines often dominated by other Lauraceae, Fagaceae and rhododendrons, where high rainfall and persistent cloud sustain the laurophyllous canopy across a broad altitudinal range.

It is an evergreen tree with smooth bark and glabrous to thinly pubescent twigs. The leaves are alternate, coriaceous, elliptic to oblanceolate, entire, with a pinnate venation of fine, looping secondary veins and an obtuse to shortly acuminate apex, often glaucous beneath. The flowers are small and bisexual, borne in subterminal or axillary panicles; they show the trimerous laurel plan with six tepals in two whorls, fertile stamens in several whorls including a third whorl with paired basal glands, and inward-facing anthers dehiscing by valves. The fruit is a globose to ellipsoid berry seated on a persistent, somewhat enlarged perianth base or cupule, characteristic of the genus.

Machilus, often treated within or close to Persea, is an Asian genus of the tribe Laureae whose delimitation has long been debated; molecular and floral evidence continues to refine the boundary between Machilus and Persea. The species is an integral element of mid-montane evergreen forest, contributing to canopy structure and providing fleshy fruits for birds. It is not currently considered threatened, though it depends on the maintenance of undisturbed humid broadleaf forest.

Author: King ex Hook.f. · Sources: POWO (Kew), Flora of China Vol. 7, Flora of Bhutan Vol. 1, GBIF, Kostermans: Lauraceae studies

Loranthaceae

Macrosolen psilanthus

by G & P Jürgens

(Hook.f.) Danser

Bhutan2012 698
Bhutan Galephu 850m, September

Description

Macrosolen psilanthus is an eastern Himalayan hemiparasitic mistletoe distributed across India, Bhutan, Nepal and Bangladesh, with about 35 occurrences concentrated in the warm subtropical foothills and duars at the base of the Himalaya. It grows as a stem parasite on the branches of a range of broad-leaved trees and shrubs in subtropical broad-leaved forest, secondary woodland and along forest edges, predominantly at low elevations below about 1200 m. The photographed plant from Galephu in southern Bhutan at 850 m, flowering in September, is typical of its occurrence in the humid, low-altitude foothill forests of the eastern Himalayan front, where suitable host trees are abundant.

It is a glabrous, woody aerial hemiparasite attached to its host by a haustorial connection. The branches are terete to somewhat angled, and the leaves are opposite, coriaceous, ovate to elliptic-lanceolate, entire, with pinnate venation and a short petiole. The inflorescences are axillary spikes or racemes bearing opposite, decussate flowers, each subtended by a single bract. The flowers are bisexual with a calyculus crowning the inferior ovary and a tubular, six-merous corolla that is reddish, orange or greenish-yellow, the lobes reflexing at anthesis; the epithet psilanthus ("smooth-flowered") refers to the glabrous perianth. The six stamens are epipetalous. The fruit is a one-seeded berry whose seed is enveloped in viscin.

Macrosolen belongs to the Loranthaceae, the showy-flowered mistletoes, and like its relatives is an obligate hemiparasite drawing water and minerals from its host while photosynthesising in its own green leaves. The flowers are bird-pollinated (ornithophilous), and the viscin-coated seeds are dispersed by frugivorous birds such as flowerpeckers that deposit them on host branches. The species is locally frequent within its foothill range and is not considered threatened.

Author: (Hook.f.) Danser · Sources: POWO (Kew), GBIF, Flora of Bhutan Vol. 1, Flora of Nepal, Barlow Loranthaceae revisions for the Malesian and Asian region (monograph), Flora of British India

Rosaceae

Maddenia himalaica

by G & P Jürgens

Hook.f. & Thomson

Bhutan2014 585
Bhutan Phobjika 3100m, May

Description

Maddenia himalaica is a Himalayan and Sino-Himalayan species recorded from Nepal, north-east India, Bhutan and south-west China, the 68 georeferenced occurrences including a few cultivated points in Belgium and the United States. It is a plant of cool temperate forest margins, ravines, streamsides and shrubberies, often in association with mixed broadleaved and conifer woodland. The Bhutan material was gathered at Phobjika at about 3100 m, within its usual elevational band of roughly 2400-3600 m in the upper temperate zone. Under current taxonomy GBIF treats the name as a synonym, with Maddenia himalaica regarded as the accepted name; the genus is now frequently subsumed within Prunus.

It is a deciduous shrub or small tree with glabrous to finely pubescent young branchlets and conspicuous, persistent, fringed stipules. The leaves are alternate, oblong to obovate-elliptic, acuminate, sharply and often doubly serrate at the margin, with prominent venation. The small flowers are crowded in short, dense racemes and are apetalous or nearly so, a key generic feature; the numerous stamens surround a glabrous ovary. The fruit is a small ovoid drupe, blackish at maturity, seated on the persistent hypanthium.

Maddenia has long been placed in subfamily Amygdaloideae near Prunus and Pygeum, and molecular studies support its inclusion within a broadly circumscribed Prunus, the reduced apetalous flowers being a derived condition. Its dense racemes attract small insects, and the drupes are dispersed by birds. Widespread if scattered across the Himalaya, it is not considered threatened, though its forest habitat is locally reduced by clearance and grazing.

Author: Hook.f. & Thomson · Sources: POWO (Kew), GBIF, Flora of Bhutan, Flora of China, Flora of Nepal, Rehder Manual of Cultivated Trees and Shrubs

Magnoliaceae

Magnolia globosa

by G & P Jürgens

Hook.f. & Thomson

Sikkim2011 191
Sikkim Lachung 2800m, June
Sikkim2011 193
Sikkim Lachung 2800m, June

Description

Magnolia globosa is a small deciduous tree or large shrub of the eastern Himalaya and adjacent China, documented by GBIF (236 occurrences) from China, India, Bhutan and Nepal, with additional records reflecting cultivation in Europe, Korea and elsewhere. It is a plant of cool, humid temperate forest, growing in mixed broadleaved and conifer woodland, along ravines and on shaded slopes, generally between about 2500 and 3500 m. The collection from Lachung in Sikkim at 2800 m in June represents its typical montane forest habitat, where it flowers in early summer in the moist, mist-laden middle-mountain belt.

The species is a spreading, often multi-stemmed tree whose young twigs, petioles and flower buds bear conspicuous rusty or pale tomentum. The leaves are alternate, broadly ovate to elliptic, rounded to cordate at the base and pubescent beneath. The flowers are nodding and characteristically cup-shaped to nearly globose, fragrant, with creamy-white to ivory tepals; the perianth is differentiated into a few outer and several inner tepals surrounding numerous spirally arranged stamens and an elongate gynoecium of free carpels. The fruit is an aggregate of follicles forming a cylindric to ovoid pink to crimson cone, releasing red-arillate seeds at maturity.

Magnolia globosa belongs to the morphologically ancient Magnoliaceae, a family noted for spirally arranged floral parts, apocarpous gynoecia and beetle pollination of the large protogynous flowers. Its nodding globose blooms and aggregate follicular cone are diagnostic. Though valued in horticulture, wild populations are scattered and the species, like many temperate Himalayan magnolias, is potentially vulnerable to forest loss and so warrants monitoring.

Author: Hook.f. & Thomson · Sources: POWO (Kew), GBIF, Flora of China Vol. 7, Flora of Bhutan Vol. 1, Flora of Nepal, Hunt Magnolias and their Allies