Trending Now. Answers. Best Answer: The sieve-tube cells, also known as sieve-tube members, are the more advanced type of conducting cell, and are the only sieve element found in the phloem of angiosperms.[3] The sieve tube is an elongated rank of individual cells, arranged end to end, and functioning to conduct food materials throughout the plant. The sieve areas of these cells are called sieve plates; the pores in sieve plates are generally larger and more variable in size.