America's Source for High School Sports and the leading volleyball organization team up to honor the nation's best. (Week of 9/2-10/4).
Phloem Structure Phloem is composed of several cell types including sclerenchyma, parenchyma, sieve elements and companion cells. The sieve element and companion cell are found closely associated with each other in what is referred to as the sieve element/companion cell complex.
They are primitive plants and their leptoids and hydroid cells act like xylem and phloem, but the cell walls do not have lignin in them, so they are not true xylem and phloem cells.hey are primitive plants and their leptoids and hydroid cells act like xylem and phloem, but the cell walls do not have lignin in them, so they are not true xylem and phloem cells.