#17 "Stem Structures"
Color Code For This Page
- Red: apical meristem (g), maple bud scales (i), and procambium (p)
- Green: leaf primordia (a), leaf (b), node (c), stem internode (d), bean terminal bud (e), and bean axillary bud (h)
- White: stem axis (f)
- Tan: lilac bud scales (i) and leaf scar (m)
- Dark brown: bud scale scars (j), bundle scars (n), and lenticels (o)
- Gray-pink: stem growth, last year (k)
- Gray: stem growth, 2 years ago (l)
The major functions of the stem are conducting materials, support of the shoot system, and food storage.
Part of a Stem
Shoot Tip: The stem shoot apex produces leaf promordia (a) that develop into leaves (b).
Node: A node (c) is a place where a leaf or leaves arise on the stem.
Internode: The elongated portion at the end of the stem between two nodes (d).
Bud: A terminal bud, which develops at the end of the stem, encloses a meristematic stem axis (f) with its apical meristem (g). Axillary buds (h) are lateral buds that form at the leaf-stem axils and may develop into lateral vegetative shoots or flowers.
Bud Scales: Small, modified leaves that cover and protect the bud (i). Some buds lack scale coverings and are called naked buds.
Bud Scale Scar: Perennial woody stems exhibit scars (j) at the sites where terminal bud scales were shed during previous years (k, l).
Leaf Scar: A scar remains on the stem where a leaf stalk (petiole) was attached. Leaf scars (m) and buds are species-specific and, therefore, are useful for winter plant identification.
Bundle Scar (Leaf Trace): The vascular bundles (n) from a shed leaf appear as dots within a leaf scar.
Lenticel: Openings for gas and water exchange in the stem surface (o) are found on some plants with secondary growth.
Color Biogram #17, answer these questions and add both of them to your portfolio.