What is Kingdom Plantae and what organism included in Plantae?

Kingdom Plantae :  includes organisms that are eukaryotic, multicellular, photosynthetic. Their cells also contain pigments of carotenoid and chlorophyll a and b in chloroplasts, and have cell walls made of cellulose.

Most plants, according to the current classification scheme, lead a terrestrial existence. Because of this, plants have evolved tissues that protect against drying out, specialized sex organs to protect the sex cells, tissues that support the photosynthetic surfaces above the ground to maximize the capture of sunlight and gas exchange, and reproductive modes that do not require water and can resist drought conditions. More advanced plant forms have also evolved organs that absorb, and tissues that conduct water, minerals, and nutrients.

Land plants include a group known as the Bryophytes. Mosses and liverworts are probably the best known of the bryophytes. They usually inhabit moist habitats, and range from the Arctic to the Antarctic. Obviously they are hardy plants, able to withstand extremely harsh conditions. Bryophytes are characterized by their small size and their lack of developed vascular tissues, although some species of moss do have some specialized cells that transport water and food. They have small rhizoids that serve to attach the plant, but do not absorb water and/or nutrients. Bryophytes need water to reproduce sexually.

Vascular plants can be classified as non-seed bearing, such as ferns, and fern allies, or seed bearing - gymnosperms and angiosperms.