Medicago stem cross section. The corners of the stem are collenchyma tissue. Notice phloem companion cells Tracheids of Pinus . Notice the arrangement of tracheids with pointed end. Pine wood annual ring with a resin duct.
All cells are tracheids.
However the ones formed early in the season when there is water available are larger than the ones produced later in the season. Such transition makes the distinction between annual rings in pines easy.