Unformatted text preview: Lenticils:
• gas exchange.
First cork cambium forms during 1st season.
• Subsequent cork cambia may develop in older 2o phloem.
• Result: external patterns on older bark (p.625). Alligator juniper Shagbark hickory Focus Plant 4: Periderm
Quercus Suber (Cork oak) p. 626
Mediterranean: Portugal, Spain, etc.
• woodlands & plantations have high
• Trees Live for 100’s of years.
Sustainable harvest of outer bark every 10yr.
• Chief product: Wine corks.
• The enemy: Plastic corks; Currently
20% of market.
• Oak woodlands threatened by
conversion to other uses.
conversion Harvest Cork
Leaves & Fruit Cork oak
w oodland Bark & Wood (p. 620; 587)
Wood: Inside of vascular cambium.
• Wood usually the main economic forest product. *
Bark: Outside of vascular cambium.
• Inner bark: Functional 2o phloem, active cork cambium, &
• Outer bark: Outside of active cork cambium; old periderms &
old 2o phloem. Bark Wood * F.Y.I.: See interesting supplemental slide at end of presentation for
descriptions of economic uses of various types of wood. External Features of Winter Twigs (After 1-2 Seasons Secondary Growth) p. 624; 589
• Terminal bud.
Lateral (axillary) buds.
Vascular bundle scars.
Nodes & internodes.
Bud scale scars. Chapter 25 Part 2: The Leaf
External leaf features (p. 592-593; 560-561)
Leaf stalk = Petiole.
Leaves may have a sheath.
Leaves may lack a petiole: =
sessile. Sessile leaf with sheath Arrangement of Leaves on Stem (Phyllotaxy)
(p. 590-591; 559-561).
Alternate (includes both spiral &
Whorled Basal Leaf Blade Complexity (p. 593; 559-561)
Simple: one blade.
Compound: blade completely separated into
• Palmately compound.
• Pinnately compound.
• Bipinnately compound.
Rachis: Axis of pinnately (or bi) compound
leaf. Simple Rachis Palmately compound. Pinnately
compound. Leaf Venation: (branching pattern of veins in a leaf). Parallel venation: (most monocots),
Palmate venation: Leaf / Leaflet Shapes
3-4 or more times longer than wide:
Needle-shaped: thin, not flattened.
Linear: margins parallel for much of length, flat blade.
Lanceolate: lance-shaped, widest near base.
Oblanceolate: lance-shaped, widest near tip.
Elliptic: widest at middle. Needle Linear Oblanceolate Elliptic
Lanceolate Leaf / Leaflet Shapes
Leaf less than 3 times longer than wide:
Ovate: egg-shaped widest near base
Obovate: egg-shaped widest near tip
Oval (= broadly elliptic): widest at middle Ovate Obovate Oval Leaf Bases & Tips
Acute: Margins meet at angle of less than 90o.
Acuminate: acute and drawn out into a long tip.
Obtuse: angle greater than 90o. Obtuse
Acute Obtuse Leaf Margins:
(Small projections). E...
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