Horton Plains National Park - Flora

Flora

The vegetation of the park is classified into two distinctive groups, 2,000 hectares (7.7 sq mi) of wet patana (Sinhalese for "montane grasslands") and 1,160 hectares (4.5 sq mi) of subtropical montane evergreen forests. Nearly 750 species of plants belonging to 20 families have been recorded from the park. The forest canopy reaches the height of 20 metres (66 ft) and features Calophyllum walkeri, forming communities with varieties of Myrtaceae species such as Syzygium rotundifolium, and S. sclerophyllum, and Lauraceae members including Litsea, Cinnamomum, and Actinodaphne speciosa. The undergrowth layer is characterised by Strobilanthes spp. The thickness of the Strobilanthes vegetation hinders the development of a herb layer. Dwarf bamboo species such Indocalamus and Ochlandra also found in the undergrowth layer. Rhodomyrtus tomentosa bushes specially grow in forest margin and near the mountain peaks. Species such as Gordonia and Rhododendron arboreum have spread to Sri Lanka, along the Western Ghats of South India from the Himalayas and are now common. Nearly 54 woody plant species have been recorded from the park, of which 27 (50%) are endemic to Sri Lanka.

Frequent fire and grazing characterises Plagioclimax communities of the grassland flora. Grasslands are dominated by Arundinella villosa and Chrysopogon zeylanicus. Waterlogged swamps or slow moving streams are found in low lying areas, and macrophytes such as Aponogeton jacobsenii, sedge species Isolopis fluitans and Utricularia spp. are found near the slow moving streams. The bamboo Chimonobambusa densifolia thrive along the banks of the streams, and near the swampy areas grass species such as Juncus prismatocarpus, Garnotia mutica, Eriocaulon spp. and Exacum trinervium are common. Tussock grasses such as Chrysopogon zeylanicus and Cymbopogon confertiflorus are found in the wet hollows. Herbaceous flora of the grasslands include temperate species including Ranunculus, Pedicularis, Senecio, Gentiana and Alchemilla and also tropical species such as Eriocaulon and Ipsea speciosa (a rare endemic daffodil orchid). The most widespread boreal herbaceous plants of the park are Viola, Lobelia, Gaultheria, Fragaria, and Plantago.

Tree trunks and branches are ornamented with many species of ferns, Lycopodium, lichens, and orchids. Old man's beard (Usnea barbata) hanging from branches adds to the beauty of the forests. About 16 of the orchid species being endemic. Other notable plants include shrubs such as Rhodomyrtus tomentosa, Gaultheria fragrantissima, herbs, Exacum trinervium, E. walkeri, Drosera indica, and tree ferns Cyathea spp. Anzia, a foliose lichen genus belonging to Parmeliaceae family, which had not been recorded in Sri Lanka previously, was discovered here in 2007. There are conflicting views on how the grasslands of the park came into being, whether man-made or natural. It is now believed that the grasslands on the dry slopes were created by forest clearance and fires while grasslands in low lying areas were naturally created by wet conditions, frost and soil erosion.