Plant fossils are found in the well-known Jurassic sedimentary basin in Puttalum District, North-Western Province, Sri Lanka. Fossil specimens were collected in a Tabbowa reservoir and the morphological characters of leaves, shoots and stems were studied. The specimens could be diagnosed as conifers belonging to the two genera Brachyphyllum and Pagiophyllum. The two genera are very similar to each other in leaf morphology. However, combined observations of transmitted light and polarizing microscopy revealed additional characters such as leaf arrangement pattern, keel cushions and dimensions, shape of leaf apices and bases. Since cuticulars are not preserved, specimens are assigned only to their genus level. Both specimens have leaf axes with imbricated, spirally arranged, scale-like leaves. This indicates their affinity with the Araucariaceae (Araucaria) or Cheirolepidiaceae family. On the basis of systematic affinities the specimens could be linked to the extinct conifer family; Cheirolepidiaceae, one of the dominant plant groups during the Middle to Early Jurassic in the Gondwana landmass. Brachyphyllum serves as a thermophilic index plant species as a “climate indicator plant” of the arid paleoenvironments that prevailed at the beginning of the Jurassic period. Therefore the collected fossils confirm arid and dry conditions in the Middle Jurassic of Sri Lanka. Keywords: conifer, Brachyphyllum, thermomorph, paleoenvironment Introduction: The Tabbowa Jurassic sedimentary deposit is a terrestrial deposit in a faulted basin rich in plant macrofossils compared to two other known Jurassic localities in Sri Lanka. This environment presents a rich and diversified floristic complement made up of ferns, seed ferns, cycads and conifers. Among these Sitholey (1942) describes... half of the article ......and the Tabbowa flora consists of small to needle-like leaves expected to characterize a relatively dry climate. The presence of the cheirolepidiaceous plants Brachyphyllum and Pagiophyllum favors drought conditions and Brachyphylum served as a climate indicator plant of the Lower Jurassic period. Therefore, the Tabbowa plant group may represent the hot, dry climate of the Middle Jurassic period. References: Harris, T.M., 1979. The Yorkshire Jurassic Flora, V. Coniferales. British Museum (Nat. Hist.), London, 166 pp.Vakhrameev,VA 1987. Climates and distribution of some gymnosperms in Asia during the Jurassic and Cretaceous; Review of Paleobotany and Palynology, 51:205-212pp Vakhrameev, V.A., 1970. Range and paleoecology of the Mesozoic conifers, the Cheirolepidiaceae. Paleonthol. Zh. (1): 19-34.Works citedconifera, Brachyphyllum, Thermophila, Paleoambiente