Thin-walled cells composing the meristem, capable of division and from which other tissues are formed.
Protective Tissue.
Tegumentary System.—Epidermis, periderm, bark protecting the plant from external contact.
Mechanical System.—Bast tissue, bast-like tissue, collenchyma, sclerenchyma, afford protection against harmful bending, pulling, etc.
Nutritive Tissues.
Absorptive System.—Root hairs and cells, rhizoids, aerial root tissue, absorptive leaf glands, absorptive organs in seeds, haustoria of parasites, etc.
Assimilatory System.—Assimilating cells in leaf and stem.
Conductive System.—Sieve tissue, tracheary tissue, milk tissue, conducting parenchyma, etc.
Food-storing System.—Water reservoir, water tissue, slime tissue, fleshy roots and stems, endosperm and cotyledons, etc.
Aerating System.—Air spaces and tubes, special air tissue, air-seeking roots, stomates, lenticels, etc.