The purposes of this research were 1) to study the floristic compositionand the flowering and fruiting periods of some limestone vegetation in Khao SamRoi Yod National Park, 2) to compare the vegetation and soil differences betweenseaward side and leeward side of limestone mountains and to determine thechanging of vegetation with altitudinal gradients, 3) to study the vegetationestablishment with emphasis on important trees, shrubs, and endemic species onlimestone mountains, and 4) to study the anatomy and nutrient contents of someimportant trees and endemic species on limestone mountains and to determinetheir seed germination and seedling survival. The research was carried out byselecting four distinctive limestone mountains in the national park,establishing of transects and plots of different sizes from the base to the topof the mountains, collecting and identifying the vegetation and manipulatingdata by using quantitatively ecological methods. Categories of vegetationestablishment in this study were divided into three types. Soil samples withineach plot were brought back to determine their chemical properties. Eightcharacterized species at seaward and leeward sides were collected to probechemical compositions of roots and branches. It was found that the flora, at both seaward side and leeward side,comprised of 136 species / 6,000 m2 in 114 genera and 57 families. The tree,shrub/herb, and seedling, with highest IVI values, were ~iMallow pallidus~i(37.86%), ~iAglaonema cochinchinense~i (41.14%), and ~iM. pallidus~i (22.35%)respectively. The distribution pattern of tree species was clumpingdistribution. The peak of plant flowering was found in dry season, between Marchand April. The vegetation was different between seaward side and leeward side.The vegetation at seaward side could be categorized into three groups, while atleeward side into four groups. The chemical properties of soil were dissimilarbetween seaward and leeward sides. Soil pH was between 7.3-7.7 and the averagecontents of O.M., N, P, K, Ca, Mg, Na and CEC of soil at seaward side werehigher than those at leeward side. The number of plant species and plant densitydecreased with increasing elevations. The most vegetation establishment (> 50%)was displayed in Type 1 (establishment in pan with shallow soil or sandy soil). The leaf, branch and root anatomy of tree species was not muchstrikingly different. Generally, some species had large epidermal cells withthick cuticle, had process of calcium oxalate precipitation in leaf tissue, anddeveloped numerous intercellular spaces in the mesophyll. The number of leafstomata and leaf size of tree species at seaward side and leeward side were notsignificantly different. Most of tree species stored mineral and nutrientcontents in their roots. The seed germination of tree species was rather poorbut seedling survival was excellent.