Xylem cells tend to conduct water and minerals from roots to leaves. Tracheids are long and tapered, with angled end-plates that connect cell to cell. Vessel elements are shorter, much wider, and lack end plates. They occur only in angiosperms , the most recently evolved large group of plants. Tracheids, longer, and narrower than most vessels, appear first in the fossil record.
Vessels occur later.
Tracheids have obliquely-angled endwalls cut across by bars. The evolutionary trend in vessels is for shorter cells, with no bars on the endwalls. Image from W.H. Freeman and Sinauer Associates, used by permission. Phloem cells are usually located outside the xylem. The two most common cells in the phloem are the companion cells and sieve cells .