Plant Cells & Tissues 22-1

most flexible, thin-walled cells in plants

• parenchyma

• collenchyma

• sclerenchyma

• tracheid

elongated plant cells that occur in long strands or cylinders

• parenchyma

• collenchyma

• sclerenchyma

• cork cambium

plant cells that lack cytoplasm and other living components when mature, but thick rigid cell wall remain

• parenchyma

• collenchyma

• sclerenchyma

• guard cells

regions of rapidly dividing cells in plants

• meristems

• collenchyma

• sclerenchyma

• parenchyma

thin cylinder of meristematic tissue that can run the entire length of roots and stems

• cork cambium

• vascular cambium

• epidermis

• guard cell

lateral meristem that produces cells with tough cell walls; form a protective outside layer of stems and roots

• vascular cambium

• guard cells

• parenchyma cells

• cork cambium

layer of cells that makes up the outer covering on a plant

• guard cells

• epidermis

• tracheids

• xylem

two cells that form a stoma

• guard cells

• tracheids

• vascular cambium

• companion cells

water carrying vascular tissue

• tracheids

• xylem

• phloem

tubular cells that are stacked end-to-end forming strands of xylem

• tracheids

• phloem

• vessel elements

• companion cells