<b>Quantitative Study of Phytodiversity at Churu, Rajasthan, India</b> Biodiversity of plants collectively known as “plant genetic resources” is a key component of any agricultural production system, indeed, of any ecosystem, without which natural evolutionary adjustment of the system to the changing environmental and biotic conditions would be impossible. Plant biodiversity is an irreplaceable resource, providing raw materials for introductions, domestication as well as improvement programme in agriculture and forestry. A decline in biodiversity entails the loss of species of genes from an ecosystem with unpredictable effects for the long term survival of that system. This disappearance of species has been described as a loss of plants and animals with potential agricultural and economic value as a threat to the global climate and the environment for human existence. A population consists of organisms of a particular species, but when several populations share a common habitat and its resources, they interact among themselves and develop into a biotic community. A population consists of an organism of a particular species, but when several populations share a common habitat and its resources, they interact among themselves and develop into a biotic community. The composition of a community in any habitat is depending upon the environmental conditions and ecological amplitude of species populations. In a community, plants of one or more species are more prominent than the others because they are present in considerable numbers and largely control the environment. These are called dominants and they determine what other species may grow in the community. The members of a community compete with each other for factors of the environment such as light, water and mineral nutrients. Community structure, composition, shape and so on are called qualitative features while the measurement of density, frequency of occurrence, height, coverage, and growth represent the quantitative features. Biodiversity, Population, Community, Qualitative and quantitative features 771-784 Issue-4 Volume-1 Dr. Prashant Kumar Sharma