Eastern Himalayan Vegetation

Plant Formations in the Eastern Himalayan BioProvince

Peter Martin Rhind

Eastern Himalayan Broadleaf Forest These temperate forests range in altitude from about 1500m and 3000m and stretch from the deep Kali Gandaki River Gorge in central Nepal though Bhutan and into India’s eastern state of Arunachal Pradesh. Up to about 1500m, mixed forests occur characterized by Castanopsis indica, Engelhardtia spicata and Schima wallichii. Endemic species found in this general zone include Argyreia hookeri (Convolvulaceae), Begonia rubella (Begoniaceae), Entata phaseoloides (family?), Orthosiphon incurvus (Lamiaceae), Pandanus nepalensis (Pandanaceae), Rhaphidophora glauca (Araceae), Thomsonia nepalensis (Araceae) and the epiphytic orchids Bulbophyllum affine, Coelogyne flaccida Cryoptochilus luteus (Orchidaceae). Above 1500m and extending up to about 2700m, the forests are predominantly composed of evergreen oak. These are dominated by species such as Quercus fenestrata, Q. lamellosa, Q. pachyphylla, Q. spicata, Lithocarpus pachyphylla, Rododendron arborea, Schima wallichii, Symingtonia populnea, and include the endemic rhododendrons, Rhododendron falconeri, R. thomsonii and R. virgatum (Ericaceae). Other endemics include Buddleja conilei (Scrophulariaceae) and the climbers Aristolochia griffithii (Aristolochiaceae) and Porana grandiflorum (Convolvulaceae) in the scrub layer, while in the ground layer include Arisaema griffithii, A. erubescens (Araceae), Impatiens stenantha (Balsaminaceae), Viola wallichiana (Violaceae) and the orchids Calanthe brevicorum and Vandopsis undulata (Orchidaceae). In places however the endemic grass Arundinaria maling (Poaceae) may form dense thickets in the undergrowth. Finally, the many epiphytes of these forests include endemics such as Aeschynanthus sikkimensis (Gesneriaceae), Agapetes serpens, A. incurvatus (Ericaceae), and Cymbidium longifolium (Orchidaceae).

Eastern Himalayan Subalpine Conifer and Rhododendron Forests At heights above 2700m a mixture of conifers and rhododendrons dominate the forests. Up to about 2900 m the near endemic Tsuga dumosa (Pinaceae) is the main conifer, but at higher elevations this gives way to the endemic Abies spectabilis (A. densa) (Pinaceae). Other endemic or near endemic conifers include Larex griffithiana, L. himalaica (Pinaceae) and Pinus willichiana (Pinaceae). The main rhododendron species include endemics such as Rhododendron grande, R. hodgsonii, R. wightii and R. setosum (Ericaceae), with the latter species becoming dominant in the upper limits of forest at about 4000 m. Other endemic rhododendrons found include R. cowanianum and the epiphytic R. camelliflorum and R. pendulum. The herbaceous flora is not as rich as at lower elevations but nevertheless includes a number of endemics such as Aconitum spicatum (Ranunculaceae), Cypripedium elegans (Orchidaceae), Impatiens falcifer (Balsaminaceae), Primula gracilipes (Primulaceae) and Rodgersia nepalensis (Saxifragaceae), while in forest clearing the spectacular endemic umbillifer Angelica cyclocarpa (Apiaceae) can be found growing up to 3 m tall. However, there are a number of variations in forest type. On top of Bhandukay Bhajanj, for example, at a height of about 3100 m there is a forest dominated by the near endemic Daphniphyllum himalayense (Daphniphyllaceae) associated with Rhododendron arboreum var. campbelliae, R. barbatum and R. grande. It is here that the strange vesseless dicotyledon Tetracentron sinense var. himalense was discovered - a species that has been placed in its own family (Tetracentraceae) and appears to have features in common with the primitive family Winteraceae.

Copyright © 2010 Peter Martin Rhind Eastern Himalayan Alpine Scrub and Meadow Situated between the tree line at about 4000m and the snow line at about 5500m, this habitat complex supports one of the richest floras in the world with some 7000 species. The scrub vegetation is dominated by many colourful rhododendron species often forming distinct assemblages of endemic or near endemic species. In eastern Nepal these include Rhododendron campanulatum, R. campylocarpum, R. thomsonii, R. wallichi and R. wightii. Further east in Bhutan these give way to R. aeruginosum, R. baileyi, R. bhutanense, R. fragariiflorum, R. pogonophylum, R. pumila and R. succothii, while still further east the main species are R. calciphila, R. chryseum, R. crebriflorum, R. riparium, R. saluenseum and R. sanguineum (Ericaceae). However, even the rhododendrons are often less conspicuous than the bright yellow flower stalks of the endemic Nobile rhubard Rheum nobile (Polygonaceae). Other endemics associated with the alpine scrub include Aconitum gammiei (Ranunculaceae), Berberis angulosa, B. erythroclada (Berberidaceae), Cicerbita macrantha (Asteraceae), Codonopsis thalictrifolia (Campanulaceae), Corydalis juncea (Fumariaceae), Geranium refractum (Geraniaceae), Geum sikkense (Rosaceae), Hedysarum campylocarpon (Fabaceae), Lonicera cyanocarpa var. porphyrantha (Caprifoliaceae), Meconopsis simplicifolia, M. sinuate (Papaveraceae), Primula oblique and P. reticulata (Primulaceae. The alpine meadows also support hundreds of herbaceous species often producing a riot of colour in springtime. Some of the endemics found here include Astragalus floridus (Fabaceae) and Ranunculus adoxifolius (Ranunculaceae), but most of the endemics within this zone are more likely to be found on the steeper alpine slopes. These include Adonis nepalensis (Ranunculaceae), Astragalus floridus, A. stipulatus (Fabaceae), Cortiella hookeri (Apiaceae), Delphinium viscosum (Ranunculaceae), Gentiana depressa, G. prolata (Gentianaceae), Geranium nakaoanum (Geraniaceae), Hedysarum sikkimense (Fabaceae), Herminium macrophyllum (Orchidaceae), Lamium tuberosum (Lamiaceae), Lloydia flavonutans (Liliaceae), Primula wigramiana, Primula wollastonii (Primulaceae), Rhododendron glaucophyllum, R. nivale (Ericaceae), Roscoea capitata (Zingeraceae), Salix daltoniana (Salicaceae), Swertia hookeri, S. multicaulis (Gentianaceae) and Tanacetum atkinsonii (Asteraceae), while riverside slopes provide habitat for the endemic Omphalogramma elwissiana (Primulaceae) and Primula sikkimensis (Primulaceae).

Eastern Himalayan Scree Slopes Surprisingly, this often highly unstable habitat also provides habitat for many endemic species including Arenaria edgworthiana (Caryophyllaceae), Chlorophytum nepalense (Liliaceae), Gentiana urnata (Gentianaceae), Pycnoplinthopsis bhutanica (Brassiaceae), Saxifraga engleriana (Saxifragaceae), Soroseris pumila (Asteraceae), Tanacetum gossypinum (Asteraceae) and Veronica lanuginose (Scrophulariaceae).

Eastern Himalayan Rocks, Rocks Crevices and Ledges Like in many other mountain ranges, these open rocky habitats provide refuge for many alpine species and often providing ideal conditions for endemic species to develop. In the case of the Eastern Himalayas these include Begonia josephii (Begoniaceae), Codonopsis dicentrifolia (Campanulaceae), Cremanthodium nepalense (Asteraceae), Primula aureata, P. caveana, P. deuteronana, P. gambeliana (Primulaceae), Spathoglottis ixioides (Orchidaceae) and Saxifraga roylei (Saxifragaceae).

Further information required.

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