The whole island is a mass of land where the plant life is very rich and vibrant with all shades of Green colour leaves. There are around 3500 Flora species in Sri Lanka and about one quarter of that is endemic to the country.
Diversity and endemism of plants in Sri Lanka are quite high. There are 3,210 flowering plants belonging to 1,052 genera. 916 species and 18 genera are endemic to the island. Additionally, all but one of the island’s more than 55 dipterocarps are confined to Sri Lanka. Although not lately assessed, Sri Lanka’s ferns are estimated at about 350 species.

Diversity, richness, and endemism across all taxagroups are much higher in the wet zone than in the dry zone. Wet zone, which accounts for only a quarter of Sri Lanka’s land area, harbours 88 percent of the flowering plants, and 95 percent of country’s flowering plant endemics. The natural forests of Sri Lanka are categorized into eight types

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The vegetation types of the island mainly varies with the climate and the topography. The rainfall and the temperature are the most important factors of the climatic conditions.
There are four major zones of vegetation types in Sri Lanka.

The Arid Zone has a temperature between 32-36 degrees Celsius. The Rainfall is below 100 mm per year and the Altitude is less than 300 meters. The forest type is referred as Tropical Thorn Scrub.

The Dry Zone has a temperature between 28-32 degrees Celsius. The Rainfall is between 1000-1500 mm per year and the Altitude is less than 500 meters. The forest type is referred as Tropical Dry Mixed Evergreen.

The Intermediate Zone has a temperature between 24-28 degrees Celsius. The Rainfall is between 1250-2000 mm per year and the Altitude is between 500-1500 meters. The forest type is referred as Tropical Moist Evergreen.

The Wet Zone has a temperature between 16-28 degrees Celsius. The Rainfall is above 2000 mm per year and the Altitude range is divided in to three categories.
The vegetation type in the altitude range of between 300-1000 meters is called as Tropical Lowland Wet Evergreen forests.
The vegetation type in the altitude range of between 900-1500 meters is called as Tropical Sub Montane forests.
The vegetation type in the altitude range of above 1500 meters is called as Tropical Upper Montane forests.

Some important flora species [of Trees] found at Peradeniya Botanical Garden is displayed with Species and Family description with the local Sinhala name with many photographs.
The World heritage Sinharaja Rain Forest ‘s Flora species such as Navanda or Nava Dun (Shorea stipularis), Hora (Dipterocarpus zeylancus), Bu Hora(Dipterocarpus hispidus) which are Emergent Tree types and Maha Kuratiya (Syzygium rubicundum) ,Tiniya Dun (Shorea trapezifolia), Kiri Hembiliya(Palaquium grande), Honda Beraliya ( Shorea megistophylla), Pini Beraliya (Shorea disticha), Diya Na (Mesua thwaitesii), Na (Mesua ferrea) , Dun (Shorea zeylanica) and Pelan (Bhesa ceylanica) of the Canopy layer trees are pictured here. Koti kan Beraliya (Shorea cordifolia), Rath Beraliya ( Hopea jucunda), Galmora (Pometia eximia),Keena (Calophyllum tomentosum), Ela Kirihembiliya (Palaquium canaliculatum), Walu Kina (Calophyllum bracteatum) and Dotalu (Loxococcus rupicola) of Sub Canopy layer trees at Sinharaja reserve also are figured here with many other important species of tropical trees.Endemic Trees of Sinharaja Forest Reserve.