•  Floristic Composition 
  •                      In the Sinharaja, floristic studies of nearly 17,000 trees and woody lianes above 30 centimeters girth revealed the presence of 211 species belonging to 119 genera and 43 families. Several new species have been discovered recently and about 15 species still remain to be fully identified.Studies carried out on the under-storey vegetation below the girth limit of 30 centimeters revealed that almost 50% of the total number of species in the forest were confined to this group.

                      Several plant species known to be from the Sinharaja have not been recollected in recent years, while others which were thought to be extinct for a century or so, have been re-discovered e.g. ferns such as Lindsaea repens, Tectaria thwaitesii and the Rutaceae shrub Glycosmis cyanocarpa. Within the last decade some new species too have been described e.g. Dysoxylum peerisii (Na-Imbul) and Mastixia nimali (Diyataliya) named after the two scientists Savitri and Nimal Gunatilleke who pioneered botanical studies in the Sinharaja.

    A rare fern (Lindsaea repens)
    Detail of leaf          

                        The dominant species and families in the sites studied have been summarized in Table 5. Although Mesua nagassarium often shows single species dominance in some areas, it also seems to be in co-dominance with Dipterocarp species in others. Sometimes it can even be totally absent. The species composition of the canopy seems to vary greatly, and no two sites have the same combination of the dominant species. the sub-canopy usually has several species in co-dominance. In contrast, among the under-storey trees, treelets and shrubs and the ground herbs, two species seem to be co-dominant in each stratum and these species do not seem to be site specific. In other words, the under-storey of the forest appears to be more uniform in its dominant species than the sub-canopy and canopy layers.

                A rare orchid, locally known as Wesak (Dendrodium macarthiae) found in Sinharaja. It is an ephyphite with purple flowers. The flowering season is mostly in May, coinciding with the Wesak season celebrated by Buddists.

      A rear endemic plant "Binara" (Exacum trinervium)

           Keena (Calophyllum thwaitesii)

    Cyathea sinuata (Tree fern)
    Blechnum orientalis (Paathara)
    Cinnamomum sinharajensis
    Trigonospora zeylanica
    Table 5. Dominant plant species in Sinharaja.
      Scientific Name Common Name Family
    Canopy *Mesua Nagassarium Batu na (Clusiaceae)
     Syzygium rubicundum Kurumbattiya (Myrtaceae)
     Anisophyllea cinnamomoides Welipiyanne (Rhizophoraceae)
     Calophyllum trapezifolium Keena (Clusiaceae)
    *Shorea trapezifolia Thiniya dum (Dipterocarpaceae)
    *S. affinis Thiniya (Dipterocarpaceae)
    *S. Worthinqtoni Beraliya (Dipterocarpaceae)
    *S. megistophylla Honda beraliya (Dipterocarpaceae)
    *S. disticha Beraliya (Dipterocarpaceae)
    *S. congestiflora Thiniya dun (Dipterocarpaceae)
    *Palaquium petiolare Kiri hembiliya (Sapotacea)
     
    Sub-canopy  Chaetocarpus castanocarpus Hedawaka (Euphorbiaceae)
    *Myristica dactyloides Malaboda (Myristicaceae)
     Mesua ferrea Diya na (Clusiaceae)
    *Cullenia rosayroana Katamoda (Bombacaseae)
     
    Understorey *Garcinia hermonii Madol (Clusiaceae)
    *Xylopia championii Athuketiya (Annonaceae)
     
    Treelets & Shrubs  Aporusa lanceolata Walbombu (Euphorbiaceae)
    *Lijndenia capitellata Pinibaru (Melastomataceae)
    *Lasianthus oliganthus - (Rubiaceae)
     Psychotria nigra - (Rubiaceae)
    *Gaertnera vaginans Perathambala (Loganiaceae)
     Apama siliquosa Thapassara bulath (Aristolochiaceae)
     
    Root climbers and ground hrebs  Piper argyophyllum Wal gammiris (Piperaceae)
     Psychotria sarmentosa - (Rubiaceae)
     Carex indica - (Cyperaceae)
    *Lophtherum zeylanicu - (Graminae)
     Lindsaea caudata - (Dennstadtiaceae)
    * Endemic species