Author

G & P Jürgens

Polygonaceae

Persicaria capitata

by G & P Jürgens

(Buch.-Ham. ex D.Don) H.Gross

Bhutan2012 949
Bhutan Tumching-La 2900m, October
Bhutan2012 950
Bhutan Tumching-La 2900m, October

Description

Persicaria capitata (Buch.-Ham. ex D.Don) H.Gross is a mat-forming perennial native to the Himalaya and southern China that has become widely naturalised as an ornamental and weed. GBIF documents nearly 23,000 occurrences, with native records from India, Nepal, China and Taiwan and extensive introduced populations across Portugal, Spain, Italy, the Netherlands, Great Britain, the United States, Mexico, Brazil, Colombia, Ecuador, Costa Rica, Australia, New Zealand, South Africa, Japan and Réunion. In its native range it grows on rocky banks, walls, gravelly slopes and disturbed mid-montane ground. The Bhutanese plant photographed at the Tumching-La, at about 2900 m in October, reflects its occurrence in the cool temperate zone of the eastern Himalaya.

The plant is a low, creeping herb that roots at the nodes to form dense mats; the slender, often reddish stems bear membranous ochreae at the swollen nodes. The leaves are ovate to elliptic, frequently marked with a dark V-shaped band and sometimes tinged purple. The flowers are aggregated into small, dense, globose heads borne on slender peduncles; the perianth is pink, five-lobed and persists in fruit. The fruit is a small trigonous achene enclosed by the perianth.

Widely grown as a ground-cover ornamental, P. capitata escapes readily and is recorded as an environmental weed in parts of the Mediterranean, Macaronesia, Australasia and the Americas. Its capacity to root at the nodes and spread vegetatively, combined with prolific seed production, underlies its colonising success. The species is not of conservation concern; instead it exemplifies how a Himalayan native can attain a near-cosmopolitan distribution through horticultural dispersal and subsequent naturalisation.

Author: (Buch.-Ham. ex D.Don) H.Gross · Sources: POWO (Kew), GBIF, Flora of China, Flora of Bhutan, Flora of Nepal, Hara & Williams Polygonaceae treatments

Polygonaceae

Persicaria chinensis

by G & P Jürgens

(L.) H. Gross

Bhutan2015 92
Bhutan Galephug, 600m, October

Description

Persicaria chinensis (L.) H. Gross is a widespread, often weedy perennial of warm-temperate to subtropical Asia, now naturalised well beyond its native range. GBIF records over 12,500 occurrences spanning China, Taiwan, Japan, India, Nepal, Thailand, Myanmar, the Malesian archipelago and the Philippines, with introduced populations in Australia, New Zealand, Réunion, the United States and Jamaica. It favours moist, disturbed ground, forest margins, roadside banks, streamsides and clearings from the lowlands to mid-montane elevations. The Bhutanese plant photographed at Galephug, at about 600 m in October, reflects its abundance in the humid foothill belt of the eastern Himalaya.

The plant is a sprawling to scrambling herb with branched, often reddish stems that are swollen at the nodes and sheathed by membranous ochreae characteristic of the family. The leaves are ovate to ovate-lanceolate, frequently with a dark chevron-shaped marking, and taper to an acute apex. The inflorescence comprises numerous small, capitate clusters of flowers; the perianth is white to pinkish and five-lobed, becoming fleshy and bluish-black in fruit. The fruit is a trigonous achene enclosed by the persistent, juicy perianth, which gives the fruiting heads a berry-like appearance.

Segregated by some authors as Polygonum chinense, the taxon is morphologically variable, and several varieties and forms have been recognised across its vast range. Its fleshy fruiting perianth promotes endozoochorous dispersal by birds, contributing to its colonising success and to its status as an invasive in several introduced territories. The species is of no conservation concern; rather, its broad ecological amplitude and ready establishment on disturbed soils make it one of the more conspicuous and adaptable knotweeds of monsoonal Asia.

Author: (L.) H. Gross · Sources: POWO (Kew), GBIF, Flora of China, Flora of Bhutan, Flora of Nepal, Hara & Williams Polygonaceae treatments

Orchideaceae

Phalaenopsis taenialis

by G & P Jürgens

(Lindl.) Christenson & Pradhan

Bhutan2014 674
Bhutan Wangdi 2280m, May
Bhutan2014 676 scaled
Bhutan Wangdi 2280m, May
Bh2008 511 G785
Bhutan Chongsakha, 1800m April

Description

Phalaenopsis taenialis is a small epiphytic orchid distributed through the eastern Himalaya and adjacent regions, recorded from China, India, Nepal, Bhutan, Vietnam and Myanmar, with about 161 georeferenced occurrences. It grows on tree trunks and mossy branches in humid, broadleaved evergreen and semi-evergreen forest of the subtropical to lower temperate belt, broadly between 1500 and 2500 m. The cited Bhutanese localities at Wangdue (2280 m) in May and Chongsakha (1800 m) in April are typical of its moist, sheltered mid-elevation forest habitat, where it flowers in spring before the full monsoon.

It is a dwarf, monopodial epiphyte, often nearly leafless at flowering, with a short stem bearing well-developed, flattened, photosynthetic roots that clasp the bark. The leaves, when present, are few, thin and elliptic, and may be shed during the dry season. The inflorescence is a slender raceme of small, delicate flowers; the sepals and petals are pinkish to pale lilac, spreading, and the three-lobed labellum is the distinctive feature, with a callus and small lateral lobes characteristic of the species. The fruit is a dry, ribbed capsule releasing dust-fine seeds.

The species was long placed in Kingiella or Doritis and is sometimes segregated as Hygrochilus or Aerides allies, but is now treated within an enlarged Phalaenopsis following the combination by Christenson and Pradhan. Its deciduous, root-dominated habit is an adaptation to seasonally dry epiphytic perches. As a forest-dependent epiphyte vulnerable to habitat loss and orchid collection, it is of conservation interest across its range.

Author: (Lindl.) Christenson & Pradhan · Sources: POWO (Kew), GBIF, Flora of China, Flora of Bhutan, Christenson's monograph of Phalaenopsis

Acanthaceae

Phaulopsis imbricata

by G & P Jürgens

(Forssk.) Sweet

Bhutan2015 104
Bhutan Galephug 600m, October
Bhutan2015 107
Bhutan Galephug 600m, October

Description

Phaulopsis imbricata is a widespread tropical herb whose principal range lies across sub-Saharan Africa and Madagascar, GBIF recording over 2700 occurrences from countries including South Africa, Tanzania, Ethiopia, Kenya, Cameroon, Uganda, Zambia, Zimbabwe, Mozambique and Madagascar. The Himalayan material represented here, photographed in Bhutan at Galephug at 600 m in October, lies at the lowland subtropical margin of its distribution, where it occurs in the warm, humid foothill belt. Throughout its range it grows in shaded, moist forest understorey, along streambanks, forest margins and disturbed ground.

It is a soft, decumbent to ascending perennial or annual herb with quadrangular, often rooting stems. The leaves are opposite and frequently markedly anisophyllous (unequal in each pair), ovate to elliptic, with entire to undulate margins and pinnate venation. The flowers are borne in dense, secund, imbricate, spike-like cymes subtended by conspicuous, overlapping, often whitish or pale bracts, from which the epithet derives. Each flower has a small, white to pale bluish, two-lipped tubular corolla, two or four stamens, and a bilocular ovary. The fruit is the characteristic acanthaceous loculicidal capsule with a retinaculate (jaculator) seed-ejection mechanism.

The species belongs to the Acanthaceae (subfamily Acanthoideae) and is the type and most variable member of the small Old World genus Phaulopsis. Its enormous geographic and ecological amplitude has generated considerable infraspecific variation and a long synonymy. As a tolerant colonist of forest edges and disturbed sites it is not of conservation concern; its disjunct presence in the eastern Himalaya illustrates the Afro-Asian links of moist tropical floras.

Author: (Forssk.) Sweet · Sources: POWO (Kew), GBIF, Flora Zambesiaca, Flora of Tropical East Africa, Flora of Bhutan, monograph of Phaulopsis (Manktelow)

Hydrangeaceae

Philadelphus tomentosus

by G & P Jürgens

Wall. ex G. Don

Sikkim2011 33
Sikkim Lachung 2600m, June
Sikkim2011 177
Sikkim Lachung 2600m, June
Sikkim2011 390
Sikkim Lachung 2600m, June

Description

Philadelphus tomentosus, the Himalayan mock-orange, is native to the temperate Himalaya, ranging from Nepal through Sikkim and Bhutan into northern India and SW China, with the many additional GBIF country codes (US, DE, BE, GB, PL and others) reflecting its wide cultivation as an ornamental shrub rather than a natural range. Some 388 occurrence records underpin this. The photographed plant was found at Lachung in northern Sikkim at about 2,600 m in June, at the onset of flowering. In the wild it is a shrub of temperate forest margins, ravines, open slopes and streamsides, typically between 1,800 and 3,000 m, often among mixed broadleaf and conifer woodland.

It is a deciduous shrub with arching branches and exfoliating bark on older stems. The leaves are opposite, ovate to ovate-lanceolate, acuminate, with a denticulate margin and three to five main veins from the base; the lower surface is densely tomentose with greyish hairs, a character giving the species its epithet. The flowers are borne in terminal racemes or panicles and are fragrant, with four white obovate petals, a cup-shaped hypanthium, four sepals and numerous stamens surrounding a four-locular inferior ovary tipped by partly divided styles. The fruit is a small woody capsule dehiscing loculicidally to release numerous minute seeds.

The genus Philadelphus is centred on the Northern Hemisphere and is taxonomically complex owing to hybridisation and horticultural selection; the leaf indumentum and floral dimensions distinguish P. tomentosus from related Asian species. Long valued in gardens for its scented blossom, it has naturalised in parts of Europe and North America. It remains common in its native montane forests and is of no conservation concern.

Author: Wall. ex G. Don · Sources: POWO (Kew), Flora of China Vol. 8, Flora of Bhutan Vol. 1, GBIF, Hu: A Monograph of the Genus Philadelphus

Lamiaceae

Phlomoides bracteosa

by G & P Jürgens

(Royle ex Benth.) Kamelin & Makhm.

Nepal 99 353 ergebnis
West-Nepal Kalmura 3700m, June
Garh 07 209 ergebnis
India Garhwal Panwali 3300m, June

Description

Phlomoides bracteosa is a robust perennial herb of the alpine and subalpine zones of the western and central Himalaya and adjacent Central Asia. Its distribution, documented from over 330 georeferenced records, spans India, Pakistan, Nepal, Afghanistan, China, Bhutan and Kazakhstan, reflecting a broad Irano-Turanian to Sino-Himalayan range. It favours open grassy slopes, forest margins, moist meadows and stabilised screes, typically between 2500 and 4000 m. The accompanying material was gathered at Kalmura in West Nepal at 3700 m and at Panwali in Garhwal, India, at 3300 m, both in June, near the onset of the monsoon flowering peak.

The plant forms erect, quadrangular, often purplish stems arising from a stout rootstock, reaching 0.5-1 m. The leaves are opposite, broadly ovate to cordate, rugose above with an impressed venation, crenate-serrate at the margin, and densely tomentose beneath. The inflorescence consists of several remote, many-flowered verticillasters subtended by conspicuous, often coloured and ciliate floral bracts that give the species its epithet. The two-lipped corolla is pink to purple, the upper lip galeate and bearded, enclosing didynamous stamens; the calyx is tubular with subequal teeth. The fruit is a schizocarp of four smooth trigonous nutlets.

The species belongs to a complex once treated under Phlomis, now segregated into Phlomoides on the basis of corolla, stamen and nutlet characters supported by molecular phylogenetics. It is a frequent component of Himalayan tall-herb and grazing communities, visited by long-tongued bees and bumblebees. Though not formally assessed, its wide range and tolerance of disturbed pasture suggest it is not currently threatened.

Author: (Royle ex Benth.) Kamelin & Makhm. · Sources: POWO (Kew), GBIF, Flora of Pakistan, Flora of China, Annotated Checklist of the Flowering Plants of Nepal, Kamelin & Makhmedov revision of Phlomoides

Lamiaceae

Phlomoides macrophylla

by G & P Jürgens

(Wall.) Kamelin & Makhm.

Nepal 99 380 ergebnis
West-Nepal Linji-Khola 3250m, June

Description

Phlomoides macrophylla is a Himalayan and Central Asian perennial mint distributed across Nepal, India, Pakistan, Bhutan, China and Afghanistan, with GBIF documenting roughly 120 occurrences along the main Himalayan arc and its western extensions. It occupies cool temperate to subalpine habitats, growing on open grassy slopes, in forest clearings, among shrubberies and on rocky banks, generally on well-drained soils in sunny to lightly shaded situations. The collection from Linji-Khola in western Nepal at about 3250 m in June is characteristic of its preferred subalpine elevation and its early monsoon flowering, when the herb-rich meadows of the inner valleys come into bloom.

The plant is an erect, robust perennial herb arising from a thick rootstock, the quadrangular stems clothed in stellate and simple hairs. As the epithet indicates, the leaves are conspicuously large, ovate to broadly cordate, with a crenate to serrate margin, a rugose upper surface and a densely tomentose, paler lower surface, the basal leaves long-petiolate and the upper ones reduced. The inflorescence comprises several dense, many-flowered verticillasters in the upper leaf axils, subtended by linear-subulate, often spinescent bracts. Each flower has a tubular, ribbed and toothed calyx and a strongly two-lipped corolla, typically purple, pink or pale violet, the hooded upper lip bearded and arching over the spreading three-lobed lower lip. Four didynamous stamens lie beneath the galea, and the gynobasic style yields four nutlets.

Described by Wallich and transferred to Phlomoides by Kamelin and Makhmedov, the species reflects the modern segregation of the herbaceous, rhizomatous Asiatic phlomises from the shrubby Mediterranean genus Phlomis s.str., a division supported by molecular phylogenetic study within tribe Phlomideae. Several Phlomoides species are used in regional folk medicine and as forage. Widespread and locally common in suitable montane grassland, P. macrophylla is not currently considered threatened, though it depends on the persistence of undisturbed subalpine meadow vegetation.

Author: (Wall.) Kamelin & Makhm. · Sources: POWO (Kew), GBIF, Flora of China, Flora of Pakistan, Flora of Bhutan, Mathiesen et al. phylogeny of Phlomoides

Arecaceae

Phoenix loureiroi

by G & P Jürgens

Kunth

Bhutan2012 770
Bhutan Zemgang 1600m, October

Description

Phoenix loureiroi Kunth is a small date palm broadly distributed across South and Southeast Asia, recorded by GBIF from Taiwan, India, Thailand, China, Vietnam, Nepal, Myanmar, the Philippines, Laos, Pakistan, Cambodia and Bhutan, with cultivated occurrences in the United States, Cuba, Brazil and Spain, totalling over 2000 records. It grows in open forest, savanna, grassy slopes and rocky hillsides from the lowlands into the lower montane zone, tolerating seasonally dry, fire-prone ground. The Bhutanese material from Zhemgang at 1600 m in October reflects its presence in the warm subtropical foothills.

It is a small, often clustering palm with a short, sometimes subterranean stem clothed in persistent leaf bases, rarely forming a slender erect trunk. The leaves are pinnate and arching, the leaflets (pinnae) linear-lanceolate and stiff, the lower ones modified into sharp spines (acanthophylls), a defining feature of Phoenix. The plants are dioecious, the inflorescences branched spadices enclosed in a spathe, the small unisexual flowers cream to yellowish. The fruit is a small ellipsoid drupe ripening purplish-black to reddish, with thin sweet flesh around a single grooved seed, dispersed by birds.

Phoenix loureiroi is a polymorphic species with several recognised varieties spanning its wide range. As a relative of the cultivated date palm, it provides minor local uses for thatch, fibre and fruit, accounting for the scattered cultivated records. Its fire- and drought-tolerant habit and broad Indo-Malesian to Sino-Himalayan distribution make it a resilient element of open landscapes, and it is not threatened, although habitat conversion locally reduces wild populations.

Author: Kunth · Sources: POWO (Kew), GBIF, Flora of China Vol. 23, Flora of Bhutan Vol. 3, Flora of Pakistan, Barrow monograph of the genus Phoenix (Palmae)

Rosaceae

Photinia beauverdiana

by G & P Jürgens

C.K.Schneid.

Bhutan2014 207
Bhutan Trachyangtsa 2120, May
Bhutan2014 208
Bhutan Trachyangtsa 2120, May

Description

Photinia beauverdiana is a temperate East Asian tree centred on China and Taiwan, with records extending to Bhutan and northern Vietnam; the roughly 2675 occurrences also reflect extensive cultivation in Europe, North America and New Zealand. In its native range it grows in mixed montane forest, the image documenting it at Trachyangtsa in Bhutan at about 2120 m in May. It occupies forest margins, open slopes, ravines and secondary woodland on well-drained soils in the cool, humid temperate belt, occurring as a scattered canopy or understorey component rather than forming pure stands.

It is a deciduous shrub or small tree with slender, lenticellate branchlets. The leaves are alternate, elliptic to oblong-elliptic, with finely serrate margins, an acuminate apex, and lateral veins running out to the teeth, turning red before autumn fall. The flowers are small and white, with five petals, numerous stamens and an inferior to semi-inferior ovary, borne in many-flowered terminal corymbs. The fruit is a small ovoid pome, ripening dark red and bearing the persistent calyx, attractive to frugivorous birds that disperse the seeds; it is the seasonal foliage colour and fruiting display that make the species ornamental.

Under GBIF this name is returned as a synonym, with Photinia beauverdiana itself standing as the accepted name; the species sits within subfamily Amygdaloideae (Maloideae) of the Rosaceae, in the pome-bearing alliance allied to Pyrus and Sorbus, and has at times been segregated into related genera as generic limits in the group are revised. Originally described by C.K. Schneider, it is widely valued in horticulture for autumn colour and red fruit. With a broad range and abundant cultivation it is of no conservation concern.

Author: C.K.Schneid. · Sources: POWO (Kew), GBIF, Flora of China, Flora of Bhutan, Photinia and Maloideae generic revisions (Rosaceae)

Rosaceae

Photinia integrifolia

by G & P Jürgens

Lindl.

Bhutan2014 22
Bhutan Sandrup 850m, May
Bhutan2014 481
Bhutan Tongsa 2000m, May

Description

Photinia integrifolia is an evergreen tree or large shrub of broad Indo-Malesian distribution, with verified occurrences across China, Indonesia, India, Sri Lanka, Nepal, Myanmar, Thailand, Bhutan, Malaysia, Vietnam, Laos, the Philippines, Korea, Bangladesh and Timor-Leste, and well over a thousand GBIF records reflecting its wide range and abundance. It grows in subtropical to lower-temperate broadleaved and evergreen forest, on slopes and along ridges, generally from near 800 up to about 2500 m. The Bhutanese material cited, from Sandrup at around 850 m and Tongsa near 2000 m, both in May, spans the altitudinal breadth of its habitat from warm foothill forest into cooler mid-elevation woodland.

The tree has smooth grey bark and bears alternate, leathery, glabrous leaves that are oblong to elliptic-lanceolate with entire (rarely obscurely toothed) margins, the integri-folious character of the epithet, tapering to a short petiole. The small white flowers are massed in terminal corymbose panicles; each has five spreading petals, numerous stamens and an inferior to half-inferior ovary. The fruit is a small subglobose pome, red ripening to dark purple-black, containing one or few seeds and readily taken by birds.

Photinia, of subfamily Amygdaloideae (formerly Maloideae), is allied to Pyrus and Sorbus, and P. integrifolia, described by Lindley, is distinguished within the Asian group by its entire-margined evergreen leaves. Ecologically it is a useful timber and fuelwood tree whose bird-dispersed pomes contribute to forest regeneration. Given its very wide distribution and frequency across South and South-East Asia, it is of least conservation concern.

Author: Lindl. · Sources: POWO (Kew), GBIF, Flora of China, Flora of Bhutan, Flora of British India