Chapter 6 - Stems

The area/region (not structure) of attachment, where leaf, bud, stem, fruit, flower, thorn, branches are attached

Stem region between nodes; no attachments

Flattened part of leaf

Stalk by which a blade is attached to a stalk

Angle between a petiole and the stem

Bud located in the axil. Contains meristematic tissue, same as terminal bud. Not all buds will produce all the potential parts (leaves, stems, flowers, etc.)

Protect buds (against water loss) while they grow, then fall off. Not all buds have them

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Trees or shrubs that loose all their leaves annually

Where a leaf was attached to a stem. Shapes can help with plant identification (triangular vs. round, etc.)

Marks (dots) within a leaf scar where the vascular bundles (vascular cylinders) were. The shape and size of the leaf scars and the arrangement and numbers of bundle scars are characteristic for each species and so can be useful in tree/plant ID.

Center of herbaceous dicot stems (parenchyma cells)

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In herbaceous stems, clumps of vascular tissue (xylem and phloem) scattered throughout the stem.

• Consist of outer bark, cork cambium, inner bark, vascular cambium and wood

• Older, non-transporting xylem • Function: support/strength; like a big cement pole through the center of the tree • Usually turns a dark color because the cells filled in with various chemicals; every tree has its own chemicals it uses; can resist fungus, etc. • Osage orange/hedge apple - chemicals keep wood from rotting for ~40 years. Branches used as fenceposts

• Newest, active-transporting xylem, but not “living” tissue • Lightest colored wood • Not always evenly-distributed around the tree (light, gravity, weather can cause damage and unevenness) • Function: transport, strength/support, some storge (sugars in winter)

• Chains of parenchyma cells • Like spokes on a wheel • Lateral transport • Provides protection against diseases • Makes very thin lines

• Periderm • Outer bark - protection from fungus/insects/animals, temperature, water loss (with suberin) • Inner bark - Phloem of the tree • Cork cambium - Between the outer and inner bark; produces the outer bark as it sloughs off

1) Adventitious stems 2) Rhizomes 3) Stolons 4) Tubers 5) Tendrils 6) Bulbs and Corms 7) Thorns

• Specialized (modified) stem * An underground stem, like bamboo; sends out runners, then sprouts

• Specialized (modified) stem. * Grows above ground, away from parent plant. Where touches ground, a new plants takes root. (strawberries)

• Specialized (modified) stem. * Grows underground and stores energy (starches). (Idaho potatoes - have eyes/nodes which sprouts new growth)

Like onions