Cross section of a stem

Cross section of a stem
Cross section of a stem: axis of a plant.
Epidermis: outer layer of the stem.
Phloem vessels: tubes that carry sap.
Cambium: new parts of the stem.
Cork: protective covering of the stem.
Pith: central part of the stem.
Xylem vessels: woody part of the stem.

Photo :

EN : Leaf margin
FR : Bords du limbe
ES : Bordes del limbo

Leaf 
          margin

The leaf margin is characteristic for a genus and aids in determining the species.