The document discusses plant tissues. It defines tissue as a group of organized cells with common origin, function and structure. There are three main types of tissues in plants: meristematic, permanent and specialized tissues. Meristematic tissue is made of actively dividing cells found in growing regions and gives rise to permanent tissues through cell differentiation. Permanent tissues include epidermis, ground and vascular tissues which make up the basic structure of plants. Specialized tissues are further classified into external and internal secretory tissues.